How to Diagnose Codes P0171 & P0174 - Lean Bank 1 & 2

Diagnosis of P0171 or P0174 Lean Code / Codes

[@israelayemoba]

I have never seen or heard a beautiful explanation on lean code like this. You must be a professor. Great lecture. God bless you

[@jimmyclyde3293]

I just brought a 2003 Suburban LT, and I have a rough idle. I changed the spark plugs and wire, and then I got these two codes. I am glad I watched your vid, now I can do a process of elimination. I do not go to mechanics anymore, because you can not tell if they are trust worthy or not. I have learned how to fix on my own cars from youtube. This vid is the most imformative and simpliest vid that I have ever ran across on youtube. Thank you very much for the information sir.

[@louieaguilar3800]

Wonderful explanation. Finally someone that can explain what to look for and how to fix it. Thank you so much.

[@michaelmudd3198]

I have 30 plus years as a backyard mechanic. Excellent presentation!

[@BWDuty605]

Outstanding video! I still haven't figured out my particular P0171 problem (already cleaned the MAF which didn't appear to have any build up, replaced the fuel filter, had replaced the fuel pump just a few months ago for an unrelated issue, and actually have a new EGR valve and EGR tube and DPFE sensor from unrelated issues as well). I'm guessing at this point a vacuum leak or O2 sensor. My vehicle is a 2000 Ranger with a 2.5L. The fuel filter actually burned up due to an improper install and the DPFE sensor had a faulty wiring harness (loose wire) and that code is now clear, and I had the P0171 previously, which is why I believe those to be unrelated issues. Oddly though, sometimes the P0171 will come on in just a few miles after a reset yet one time it took well over a week and 700 miles. Anyway I really appreciate you taking the time to share your knowledge in such a professional manner!

[@arifkamal108]

Thanks for the great video and the explanation.

[@jamiecosta1726]

Very clear and easy to understand, thanks man. I’ve got a 2002 GMC 5.3 L suburban. The fuel pump wasn’t providing enough pressure (10lbs max). It would fire up and then shut off immediately (no codes or check engine light were on) So, I replaced The fuel pump and filter(had already changed 30-40k ago), and then it ran. 👍🏼 . Shortly after it threw codes po171 & po174 -lean on Bank 1& on bank 2. Seems to run fine except at idle (5-6 hundred rpm), It’s a bit rougher than it was or should be . So I just smoke test, covered up the intake manifold (with rubber glove :-) and blew smoke into the brake booster hose. The only place smoke escaped , was from the oil fill tube / hole in valve cover after I removed the oil fill tube to be sure. I also replace the PCV valve after that because I had a new one, and now it’s only thrown code po171 bank 1 lean???? The old PCV valve didn’t seem as though it had been able to close all the way, Afterwards, it only showed code po171 lean on bank one. ??? I would just tell you? And why would the smoke come out of my valve cover with your filler tube is? Thanks for any help .

[@xUSMCx4xLIFEx]

You explain this kind of stuff SO NICELY.

[@ThePeoplesGarage]

+Zackasee_ Thank you! are you a TDWP fan?

[@xUSMCx4xLIFEx]

ThePeoplesGarage Yes sir :)

[@charlesrichards4837]

The best information delivered in the most effective way as I have ever experience.

[@mesharialamri357]

Much love from Saudi Arabia 🇸🇦. This is very useful, Thank you!

[@irvinclack2532]

Got to thank you for the clue. I recently change the air filter and shortly there after threw a lean code. Thanks to you I checked the vacuum lines and found the PCV line had been dislodged during the filter change. Problem solved thanks to your post! Great!

[@crackuhpleez]

great job, your simple explanation on what to consider is really well presented!

[@Jose87694]

Thanks for your time on putting this information together. I got an 04' Mustang V6 with three codes P0401, and those two codes (P0171 and P0174) and I am going to be on my adventure to find the cure...

[@generovinsky7228]

did not solve my problem (yet) but gives me a place to go, thanks for the tutoral.It confirms my suspicions and hope i don't need to drop that fuel tank. I do have between 50 and 60 PSI with my gauge so I should be good there. Anyway good post my friend.

[@peter555peter1]

You're absolutely correct about the Toyota MAFs. I was getting both codes on my 2002 Lexus. I swapped out the MAF, and everything is good. Good content. Keep up the great work.

[@ThePeoplesGarage]

You might not notice the idle rough, but still spray around the intake with brake cleaner and see if the idle changes. Also cleaning the MAF sensor might not do any good if its electrically faulty, it might need replaced. Those are really the only 2 things that are even remotely common on your truck to cause both of those codes to come on. If your friend has a scan tool that can read data, hook it up and get the reading for your MAF sensor, it should be about 4-7 grams per second at idle.

[@aileenwagner2576]

Thank u so much for speaking in a manner a novice can understand!! A lot of videos, the guys talk over my head and I'm struggling to understand what they mean, but u r clear, simple, and direct. Thank u so much!! U have a subscriber here!!👍👍👍

[@cypresswisteria]

Best explanatory video for these codes, in easy to understand language.

[@georgiemac3662]

I like the way you described the computer communications. Say I'm not seeing this over here and this sensor not seeing it over there. I never really thought about it that way. Kinda puts a whole different perspective into things. I like it..... you've earned my subscription

[@ThePeoplesGarage]

Both Codes for that ford are very common for either a PCV elbow behind the intake manifold, its a rubber 90 degree elbow most times. Also the Mass Air Flow sensor is common, You have to remember if you have both codes then both banks of the engine are effected. Meaning the Left and Right side of the "V-6". So all of your fuel injectors will never go out at the same time and the driver side sensor is only for one side. The PCV elbow and MAF sensor will effect both sides. Keep me posted!

[@jazzsounds8159]

I have a code p0174 in 06 hyundai sonata v6 3.3. Any help would help,

[@MrBodean2010]

I have same coded I'm really thinking it's my mass air flow sensor. I'm also having hard starts

[@tazaxx21]

Thanks for the lesson. I just picked up a super nice, low mileage 95 Thunderbird LX. 4.6 V8, leather, moonroof. To my pleasant surprise I found it has OBD II. It's throwing the P0171/P0174 code, and I think it's likely the MAF sensor... thanks again for the lesson..

[@markchimmy]

Have you found the problem?if so please let me know what it was. Thank you in advance!

[@aleung1946]

You are the best teacher, Give best explanation, I give you million dumb up My god bless u You are the best # 1

[@guyglot]

I Just want to say thank you for being a great teacher with out any bullshit and just straight to the point . I have done a bunch of digging around to see bogus bullshit and i bet i that them 39 assholes who clicked on thumbs down posted a few of them.

[@GaryMorrisjr]

Thank you, that was very well explained and I appreciate the detail you went through. Very thorough.

[@jj0rtega]

I found my PVC rubber elbows had collapsed and a hole in it.I replaced them all with the assembly that ford sells. My 1999 Expedition has four of rubber elbows on this assembly. It was $42 at the Ford dealer.Car runs good now and no "service engine soon" codes. This video was very helpful on me resolving this.

[@efstathios1]

First I really want to thank you for this video. The explanations were and are very good. Having some but not being an expert on engine repairs this was very informative. Second, your video actually explained an issue that i had not heard of. (concerning the where the leaks where and the code that would pop) Again awesome job

[@edwardcloud40]

I have a 05 lr3 and have a engine light on and the message on the screen says reduced speed something or of that nature. I just changed the spark plugs because the engine was missing. After the change it still was missing so I took it to o'riely's and they put the reader on and said my computer is fried because it wouldnt/couldn't establish communication with the reader. Any thkughts?

[@butterfly1348]

Best video Ive found, very straightforward and concise. Thank you

[@josephmorales5776]

I am a Mechanic you did a good job felicidades.

[@danachilders8821]

I need help with my 1997 ford f 150 xlt

[@louisiana8357]

@Dana Childers did you ever figure yours out? I have a f150 same issue

[@allenbetancourt2853]

First person to explain this with such understanding! Loved this!!!

[@johnwalston7000]

I have a 2010 Mustang GT that was throwing the P0171 and P0174 two months ago. I have an extended warranty and took it to the dealer for them to check out. Their diagnostic conclusion was that the o2 sensors needed to be replaced. New o2 sensors and codes cleared and I was back on the road. My mileage has dropped by almost 2mpg since that time. Last night, my check engine light went on again and my code reader shows the same codes again. You mention so many things that could cause these codes. Shouldn't the dealer have checked for vacuum leaks, MAFS, etc as part of their diagnostic process to conclude the o2 sensors were the only culprit? Thanks.

[@Zoofactory]

Learned more in this video about exhaust codes and causes then ever before. Thx. Very competent.

[@ThePeoplesGarage]

There you go! Glad to hear that!..Thanks for tuning in TJ

[@TILEROB]

Will a bad fuel pump cause it to run lean that's what my mechanic said 05 tahoe

[@theswizznowt]

Simple straight forward explanation. Great job!

[@ThePeoplesGarage]

P0171 is only the right side of the Engine, The PCV will effect both sides and have a P0174 Code also... try spray around the Right side of the engine with a brake cleaner or carb cleaner with it running and listen for a pickup in RPM for a vacuum leak..

[@luisponce1472]

Can I Unplug The Mass air flow Sensor with the Engine Running I heard if it Turns off The Sensor is Good any help??

[@cristalhernandez08]

Great presentation! I have somewhat of a idea of what I am doing but with this breakdown I 💯understand! Thank you!

[@watchdoggibson]

Also a Cracked EGR Valve Tube will cause these codes , I just replaced my EGR Valve tube and it took care of the problem .

[@arnaldomarquez3287]

watch dog G

[@stacksamill471]

I got po174 its idling rough an hesitates when I take off any idea?

[@MichelleReneFan]

Would a bad erg gasket do the same code? I have a code 174 and believe I have checked all lines and hoses. I also am not getting air through my air vents that are controlled by vacuum. I ran a smoke test and the only smoke I could find was coming through the erg gasket. Thanks

[@ronaldbrosius7488]

Great video! Another easy way to check for vaccumm leaks, or intake leaks, is to smoke test the engine, fix any leaks and should fix your problems.

[@appraisal951]

My story: I have a (used) 2005 Ford Five Hundred with P0171 & P0174 Lean Codes. After attempting to locate any air leaks, I decided to change out the air filter. The air filter was excessively dirty and oily (probably had never been changed). After replacing with a new one, I dove thirty miles and the light has go off. I have driven now over four hundred miles and still no light. I am thinking that the excessive oil or fuel smell that was coming off of the dirty air filter was causing the computer to think that the car was running too lean when really, it wasn't. So one step I have not heard anyone mention is to check the air filter. Hope it helps.

[@al.e123iis7]

i got these codes just changed the dirty air filter crossing mi fingers will update..

[@mcclurephilly91]

Alex P.I no update?

[@al.e123iis7]

@@mcclurephilly91 pools I forgot.... yes it was that. 30 bucks in parts. Give it a try.

[@mcclurephilly91]

got a Ford explorer sport Trac and it's throwing them codes. as well as a ho2 code.

[@al.e123iis7]

@@mcclurephilly91 my air filter was pretty dirty.. could be it if ur is too

[@larrymartushev2025]

Thank you, lots of info in under 10 minutes, very helpful.

[@sandman6717]

You can also check the fuel pressure regulator on the fuel rail. my ford explorer is a 98 5.0 V8 threw the same codes it ended being the fuel pressure regulator

[@mikecorleone6195]

How was it determined? I have been searching for a link between that code and fuel pressure regulator because I have tried everything else! I'm hoping it's not the fuel pump. Mine is a tscoma 2.4

[@sonolaaccordeon8288]

If the regulator fails (regulates fuel) then the right mix of air/fuel won’t be achieved. I have a 94 Chevy Colorado and I suspect it’s the fuel regulator since I already replace the ox sensor mass air sensor fuel filter Checked for leaks. Etc.

[@haroldhprittjr7007]

My sister-in-law’s car is giving her problems with a 3.5 Pontiac g6 gt it’s a rough idle and the exhaust is sucking back like a burnt valve will . I have reset the codes and used my x-tool d7 to pin in down as a p0174 code but the intake manifold gasket you bring up in your video made me wounder I’m going to use some propane an see if I can locate any . It stalled on her many times on the free way going to work I’m hoping to get it fixed for her so she’s not in a accident she’s a good church member and doesn’t have a lot I try to help her out an do what I can but sometimes I think I’m in over my head ! But your video is very helpful by explaining the way you have makes it easier and less problematic for me . Thanks a lot !

[@andatey]

Thank you for your video and the information, I have a 2002 BMW 325i. I have been dealing with these codes for about a year now and just yesterday I changed the pre cat O2 sensors and the P0171 code went away. I have not changed the other two sensors yet but I wanted to know which of the above mentioned symptoms are related to Bank one Vs Bank two lean codes. Thanks once again

[@ThePeoplesGarage]

andatey What other code is left now?

[@henrytripp6334]

Great explanation of the fuel system in these modern vehicles. I appreciate your thorough explanation of these systems. Thanks...

[@UPRR-nq6uj]

Thank You, Sir your video and explanation of the diagnosis are Excellent if I could buy you a beer through the internet it would be my pleasure..I have subscribed and look forward to learning from your expertise , keep up the great work.

[@larryshaulis3231]

I have a ford ranger xlt 2002 I really could use the help with some? S . The auto parts store gave me some engine codes p1000. C1155 . P1633. Can use some advice . Pls call me at 330-294-7328. Thank u

[@dannynguyen4857]

i liked ,very good lesson to learn for understanding and repair the car

[@wynterjones3809]

2000 Ford explorer 4.0 EFI p0171 and p0174. I have changed all the o2 sensors, MAF, coil pack, plugs and wires, hoses and the codes still occur. I guess it could be the Fuel Injectors. /Intake manifold gaskets.. Whats your take on the OTC 7448 Fuel Inj. Cleaning Tool for injector cleaning short of the physical removal of injectors for cleaning?,,,,,~

[@charlesrosemon8680]

have you fixed the problem? i am curious as to what the problem was

[@VickyGeagan]

I would also check the fuel pressure with a fuel vacuum gage could be a bad fuel pump as well happened on my 1996 f150

[@arikoenig4536]

Don't use gumout octane booster it gave me both codes ... garbage!

[@naveenpragnaratna3356]

Very clear instructions to short it out lean mixture with trouble code P171 & 174 Thank you . For helping out with your knowledge.

[@ThePeoplesGarage]

thanks for watching!

[@Fam1stMel]

My e90 is a straight 6 and is displaying both p0717 & p0174 codes. I have replaced the fuel pump and filter, maf sensor and checked my injectors. They're okay. The car cranks for 5-10 seconds before starting, every time. Where should I look next?

[@Bane92]

Should spray for air leaks before replacing parts

[@evarwilliams]

Mehn....you have no idea how much you've helped me with this vid. Thank you solo much!!!

[@blkhispanicmix]

usually, if you have that lean code on both banks you have a vacuum leak or low fuel pressure which means more air and the oxygen sensor will throw a code.... lean bank one and bank two. just a thought, everyone is in such a hurry to replace oxygen sensors just because the autozone scanner said thats what it is. lol wow, i know, anything to sell a part they dont need

[@bendadestroyer]

What if my 99 mustang gt gives P0174 and the MAF says 5.0 g/s?

[@ThatTasha38]

Very true!!!

[@abelfigueroa3146]

Lmao you got me at autozone scanner, will definitely look for a vacuum leak.

[@robertclark9235]

james hayes

[@arikoenig4536]

Just got p0171 and P0174 no codes before I added gumout octane booster to a full tank 2 tankfuls ago, can that be it? How do I fix? Only other thought is maybe MAF got dirty from all the ash floating around here in SoCal from the fires, no visible hose cracks any suggestions appreciated have to take in for a smog check thnx

[@AJ-AJ212]

2007 Toyota sequoia with 4.7L V8 . P0174 . Bank 2 lean . Bank 1 fuel trim: short 0.8 up to 2.3 Long 14.8 Bank 2 fuel trim: short 2.4 to 5.8 Long 25.9 O2 B1S1 output : 3.22 O2 B2S2 output: 3.22 MAF : at idle 0.8 lb/m Your input is greatly appreciated Thank you so much

[@brandonhowarddd]

My air filter wasn't clipped on all the way...

[@richardblay9782]

You this a good job, God bless you and gives you more wisdom 🙏

[@dezblyan5125]

good info

[@jeffwong7959]

Blyan,s video corner X.

[@juancordoba1555]

Jeff Wong biojjii

[@PackedFunk]

I finally changed intake gaskets & seems to be finally repaired. 39.00 Felpro gaskets. Thank you for all your help. Fine channel.

[@Biddybalboa]

get to the fucking point you're no Scotty kilmer

[@ThePeoplesGarage]

I literally lol'd when I read this! Thank you 😂👌🏼

[@GlycerinZ]

someone has a small attention span lol. Explaining cars isn't a quick thing. Patience, tiny grasshopper.

[@shackleford9]

scotty kilmer is a hack

[@terryjianlin]

alright man! great video! My 2001 ford f-150 v8 catalytic converter turns red on bank 1, along with a code p0171,,long fuel trim 25% at idle. So far I done leaking test with a smoke machine, there is no leak at all. MAF sensor cleaned , four O2 sensor are new, I pretty much rule out every possibility except for the last one, brunt exhaust valves. yeah one more thing have to mention, when I change the oil today, there were only about half of the engine capacity left

[@pamtreo72]

Great explanation, I leaned a lot more that I didn't think about. Great Video!!!

[@1consern]

Very good and down to the basic, Very good explaining the codes and how they work, I thank it's really going to help me on a truck I am working on .I'm not afraid to try to repair it now Thanks

[@oliviachandler983]

Thank you for this video it was extremely helpful for repairing my Audi.

[@hurtado98]

What was the situation?

[@DriverBrian]

Thank you so much for spending the time to post this. I've learned a lot. Trying to figure out p71 code and coolant leak on my Jaguar XF 4.2. Need to get through Jersey inspection this month. Will be replacing mass air flow sensor later today. Coolant leak I haven't figured out. I smell it with the hood open but see no leaks whatsoever.

[@handsomebastard305]

Could be water pump going bad

[@DriverBrian]

Turned out a leaking hose. 3rd repair shop found it. Generic replacement took 4 days to get but full flush n fill n hose replaced under $300. Turned out service station near by found it too. Wish I stopped there first. Thanks for the info. Water pump replaced 30k ago at 110k miles. Top plastic crap thermostat housing broke inside n piece stuck in fin of pump.

[@christopherfoxwallace1291]

Ever have a leak, but don't see it? Drive it until hot, coolant full . But do it at night pop the hood and with engine just turned off, use flashlight in the dark, and watch for the steam as you comb the entire engine bay including from and back of radiator.

[@jaldkajoi7862]

I threw some $ on parts for code P0174 to no avail. Mechanic hooked up his scanner to find problem in cylinder 5 bank2-- water in well from a loose radiator hose.

[@alanosman444]

I cannot tell you how helpful this video was to me. Now I have some logic to follow in helping me figure out why I get a P0174 on my f150. Thanks!

[@JohnnyMacTahoe]

Finally... the straight information. Thank you!

[@DaleHawkins-o5m]

Really nice run down and explanation of all parts associated with the error codes.

[@kenayre8554]

very good information ,showed me where to look on my 01 ford f-150 with 4.6 with po171 and p0174

[@markchimmy]

Have you ever found the problem?thank you!

[@JohnDoe-ow5dc]

Great info. Thanks for sharing. I am also a technical professional that sometimes get raided by the grammar police.....If you want or expect your technician to be a grammar major good luck with the advise you'll receive.....

[@ErickMartinez-bv3ib]

you make a lot of sense, and for the rest of people go to auto repair school. like i did. so if you want to know how to repair you cars go to school....

[@CrystalFuzz]

Why are you the best?? Such a great resource!!

[@fernandocasas4209]

I have a Ford crown vic. I have both of these codes I'm going to try the tips you gave for ford. Nice video 👍👌👏.

[@markchimmy]

Have you ever found the problem?please let me know, thank you for your response back in advance!

[@IOI769]

Very comprehensive. Thank you for your helpful vid.

[@brentron2212]

Best video on lean codes I've seen

[@thomaschaves706]

I have had this issue for years! I have a 2000 Jaguar XK8. It has had some issues, I was having a problem with the fuel pressure regulator. It had a leak and I replaced it. It dropped a valve seat and had the head repaired. I finally got the car back after a long time and it seemed all good except the old problem of codes P0174 and P0171. I actually had them before. When the valve work was done, and before I picked it up my mechanic would run the motor, well he finally ran it out of gas and blew the fuel pump. I got the pump and the filter replaced as well as a crumbled tube that connects the snorkel to the valve cover. I had earlier replaced the MAF. I realized I put a non Denso in and replaced that with a Denso MAF. I have tried spraying carb cleaner around the intake, and noticed no difference in the running engine. I am driving the car about 8 miles in to work. It will toss the codes usually toward the end of the ttrip. It occurs when I am stopped or backing up, like into my driveway on the return home. There are certain traffic lights I get stopped at where it codes. I also get a dreaded RESTRICTED PERFORMANCE alert. I can clear the codes and it will run fine. If I don't clear it will go with limp home speed for a few moments. The Restricted performance clears and it runs fine then. The P codes stay.

[@christinerose9561]

Best Video here on this issue. Period!!!! Thanks!

[@Pr0ph3cy-k5z]

Very indepth video. Thanks for taking the time to explain the inner workings.

[@dinoBMXidiot]

I just rescently got this issue, the P0171 code error and the issue had to do with the injectors but no quite whats mentioned here (them being dirty or cloged) it was acctually the plastic seals for the injectors that make contact with the head of the engine. they where too small and not sealing the space between the head hole and the injectors. At this point I guess it´s important to mention that the car was coming out of a rescent overhaul less than a month prior to the inccident,and the parts and gaskets where not all original, this including said injector seals, wich are just tiny dounut shaped plastic pices. whell the ones in my ¨rebuild kit¨ where a bit too skinny and didint snug the space neough to seal it, and thats where the extra air was creeping in making my engine shake irregularly and my check engin light to go on. I found this very educational and helpfull, You just got a new subscriber.

[@vinnyrussomanno5357]

Well made video, straightforward, Thank you!

[@robbyrobbiecausey2168]

Very well illustrated and put together. Two thumbs up!!!!

[@cecilgeorge4500]

Very informative, preciate you taking your timeout and showing this to us.

[@daveferris5465]

Cheers mate. Im getting lean in bank 1 this really helps me with where to start looking

[@pak8978]

I had exactly that 90 degree elbow problem on my 2000 E-150 Chateau with the 5.4L engine. There was a half-inch hole facing the front of the vehicle. Caused lean bank codes for both banks.

[@pw3543]

98 Ford explorer 304, 171, 174. 304 code gave me trouble last years replacing the coil pack, wires and plugs. I must have dropped the number 4 plug after purchasing new because it gave me trouble day one. Replaced the plug and 6 months ago and is idling rough when cold. Roughness smooths out after warmup. 171 and 174 lights were out for 6 months after replacing the easiest to replace 02 sensor on bank one. I'm thinking vacuum leak in manifold giving all three codes or Mass air flow may need cleaning or replacing again. What would do first. I hate to take the intake off at this time. I cleared the codes and know they will return. I learned a lot on utube channel. Thank you

[@pw3543]

I have the same rough idea i did in the last comment. 304, 171,174 code. Any ideas?

[@pw3543]

Forgot to mention the check engine blinks sometimes.

[@FERREEKAZOID]

That's a great video. Simply put, and alot of great info. Thank you.

[@luisponce1472]

Awesome Answers to These Codes very Good explanation step-by-step

[@akeemomoumi2135]

Thank you for detail analysis of the problem associated P0171 and P0174

[@jbarnold6350]

thank you for helping me with this problem.

[@oscarmorales4885]

Found the issue it was that little 90degree elbow i didn't see it until you mentioned it thanks bro.

[@bruceontheloose1708]

good info video . broke down now bank 1 & 2 running lean. loosed power running rough. start with fuel filter

[@broadspectrum8933]

This is what I encountered. I have a 07 Pontiac Grand Prix GT 3.8 supercharged Engine with about 110,000 miles on it. I had some vacuum lines replaced a rear main oil seal and my intake manifold gasket replaced because of a minor oil leak. After the repairs I was getting an intermittent P0171 code. Sometimes it would be on and sometimes it would be off, Engine temperature never really mattered. My Mechanic suggested we clean injectors, Mass Air Flow Sensor to remedy the problem. Although the car ran a little smoother the CEL would still come on. My Mechanic then suspected the Intake Manifold Gasket although had been replaced may be the culprit. Before I had him do that, I tried something on my own. I located the PCV valve which sits on top of the Supercharger in a recessed port secured by a metal cap by two 10mm bolts. Under this cap is a spring and the PVC valve is under the spring. I removed the spring and the valve, on the barrel end of the valve is an O-Ring it was worn so bad it was hard and flat the valve itself barley rattled unless it was shook real hard. I replaced the valve and the O-Ring, cleared the code and the Check Engine Light hasn't returned since and that was almost a month ago. Hope this helps anyone with a GM supercharged Engine that is getting the P0171 lean code.

[@ottomendez2404]

GREAT LECTURE, SUPER PROFESSIONAL. THANKS A BILLION....

[@lindaschaefer7917]

Before paying for any sensors or catalytic converter, do a smoke diagnostic check. I was getting lean codes 171 and 174. Smoke test ($150) found bad variable intake valve. Paid $500 (included diagnostic test) vs over $2,000 from Toyota for sensors and converter which would not of fixed anything.

[@mbrian1972]

love this video The people's garage, I'm a new subscriber.I had a brake booster that was bad had a air noise under the dash I replaced the booster before I replaced that I had codes P0171, P174 and P0455 after I replaced the booster the P0174 was gone leaving me the P0171 and P0455. I forgot to tell you I have a 1998 ford ranger 4.0 4×4 v6.I replaced the spark plugs and wires, brake booster, and fuel filter and replaced 3 big vacuum hoses that was close to the master cylinder attached to something I don't know what it was I thought maybe purge solenoid I'm not sure.I have high idle at start up then it calms down after I let it run, I also have a problem where my hvac vents inside the truck only blow out of the defrost and not any of the other vents could there be a vacuum leak causing this as well

[@XJonAye]

This is a excellent video thank you, im a little out of practice and this is a great refresher

[@arvindnijhawan2122]

i have this issue with my suburban 2014 LT 1500 code P01071 and P01714 i am going to my guy lets see what comes up. I like your video that makes me feel much comfortable thx million

[@jabjamar]

Wow… you explained this so well. Thanks

[@rayz2318]

Thanks for video. Helped me diagnose my 04 Sequoia. 👍👍

[@Rosell-h5g]

These are the kind of videos i love. Very educational

[@jamess3052]

awesome explanation . Thanks for the details

[@777jonah888]

nice vid that addresses a very common issue......thanks

[@PackedFunk]

I ended up with 171& 174, both banks. Changed fuel filter, cleaned MAS, cleaned air filter, cleared codes. 2000 Silverado 5.3 ran great for a month. Check engine light back on & hesitation when engine is around 170 degrees. Runs great cold & runs great at full 195 temperature. Hard to figure. Technition friend said idles too good to be intake gaskets.

[@z32racer1]

Brake booster could cause a vacuum leak and cause both codes to show up at once.

[@byrondeleon9836]

Excellent presentation and info. Clear and concise.

[@fontalvod]

Hi god night. I own an 07 Fusion 3.0 V6 yesterday i replaced the intake filter for a new one. I have had the k&n typhoon system for 3 years now so far so good. After replacing it i disconnected the negative terminal for 20mins in order to re learn trim fuel levels as i considered it was neccesary the old filter was horrible even if i clenaed it regulary. Start up really rough idle engine jumping all around car shaking all the way. So what i did: Electronic cleaner for MAF, MAP, cleaned connector male and female for EGR, MAP, MAF, Throttle Body and 3 front coils. Checked for vacuum leaks at typhoon duct, PCV vent hose, intake manifold. Checked torque for 7 bolts for the manifold. Everything ok checked codes got both p0171-74 then fuel pressure 60psi left 2 hour the pressure indicator did not move a bit. Went back to old air filter reset ecm no help same issue. Im lost right now going crazy only thing left is dirty fuel injectors but as you said that would be for one bank not the two of them. Any help? Thanks in advance!!!👍