Is your 4.3 misfiring ? pt1

[@u.s.a.198]

4.3 Tip to share. I had a strange stalling, skip issue and no codes. Couldn't figure it out. Thought it was the fuel pump. With the engine running I pressed on wires and hoses looking for a vaccuum leak.. I pressed a wire and the engine shut off. Magic moment. The coolant sensor connector plastic stay tab had broken off. The coolant sensor plug was half in half out. I inserted and it started right up. I removed it and it stalled.. crazy issue to locate but I wanted to share with others.

[@trinidadspeck1991]

Dude this may have saved me, about an hour ago my 98 S10 (4.3) stalled in a parking lot and when I started it up the whole truck was rocking and when I accelerate it backfires. Right now I’m checking all the wires so I’ll definitely have to check the coolant sensor

[@jeffersoncerf181]

@@trinidadspeck1991 did it save you? Lol

[@chadhuff-xz5bt]

​@@trinidadspeck1991so what was wrong with you car.

[@KarenListo]

Why would the coolant sensor cause multiple misfires

[@jmullentech]

@@KarenListo the coolant sensor can fuck up and when it does the ECM sees the resistance change and thinks the coolant temp is below zero (can't remember now off top but I wanna say it reads -40F). When the ECM sees that low of a temp, it tells the injectors to start dumping fuel in an attempt to get the temps up quickly and too much fuel in the cylinders causes misfires, stalling, etc. Mine was stalling randomly at stop lights and shuddering HARD randomly under load (made me think it was a torque converter issue tbh). Had no active/pending codes but I did some data logging and noticed the ECT reading dropping, fuel trims going off the scale and then engine stalling. Fucked around and wiggled the wires with it running and it did the same thing. I ended up finding a spot where one of the wires had gotten rubbed through in the harness, cut the bad shit out and butt spliced it, she's good to go now. So yeah, hope this helps.

[@JodBronson]

*Listen to this man.... He's giving you good FREE INFO in this video!*

[@willsteele9249]

by far one of the best videos for a 4.3 motor thank you

[@mikecastleberry9671]

Just replace the part no talking for a year replace about 400.00 worth of parts and just drive the bitch for years .....

[@zachfox5969]

1. Unplug your MAF. Believe it or not, this can help- if your MAF is bad or dirty. 2. Check your operating temperature. Not at the dash, mind you. Get a 25$ scan tool and compare dash temp with live data temp. Change thermostat if needs be. THIS IS WHAT FIXED MINE. If it doesn't get to the 190° or so it's supposed to be at, it'll limp instead of blowing itself up...until it blows itself up that is. 3. Clean the ever loving shit out of your EGR. Like as in 2-3 cans of carb cleaner. In between each can, swab out EGR and do it again until it drains out clear. 4. Make sure water hasn't penetrated your distributer cap. Aftermarket non vented caps can collect condensation. It may be dry as a bone in there, but if there's a burn mark on the inside of the cap, it's arcing. Get an AC Delco. While you're at it, make sure your wires aren't touching anything metal. An easy way to check this is to look under the hood in the dark while it's running. Arcing will be obvious. Hopefully this helps someone- before they spend a shit load of money on parts you don't need.

[@stephenmatthews6305]

Finally I found a channel with somebody who's knowledgeable actually very technically knowledgeable and explains it quite well baking fluently. This is a great channel the only other one I found I like is Scotty Kilmer, who is retiring very shortly.I will subscribe and watch all your blazer videos, I have one just like it and having lots of issues.

[@Keegan_Lynch]

This is the most helpful info I’ve gotten on my 4.3 misfire issues. I was going to start with fuel pump/filter and distributer and maf sensor. I need to go back in with my scan tool and check fuel pressure and other info. Thanks again man!

[@OnlyProven]

It’s the distributor I literally had this problem and changed everything around the distributor I finally changed the whole thing and she runs better than ever

[@jeffersoncerf181]

Brand new EGR valve and solenoid and still runs like crap… LIES…

[@Keegan_Lynch]

@@jeffersoncerf181 what else have you tried? Spider injectors are kinda known for cracking and causing a misfire too

[@djlemo3321]

This video solves my problem in my Astro van I had no codes but on start up it will idle poorly but would drive fine when it warm up....

[@jamiel3504]

Excellent information and thank you, and your absolutely right, these 4.3 will make you pull your hair out lol, I personally love my 4.3 and the distributor cap I replaced a year ago with the gold connectors has started and ran great until last week, I’ve got a random misfire, racked my brain thinking why? Just completed an 8 hr round trip and it did amazing, now the misfire, I’m picking up a new egr valve today because who knows when it was last replaced.

[@treedubya]

Great explanations on the why and how of the system. Helps to better understand the functions and failures of the parts in scope of the whole.

[@mikewitte7379]

On my 2000 express 4.3 the distributor sensor was intermittent and replacing it fixed the problem. 35.00 after i replaced the EGR Plugs Wires Cap. Just saying its worth changing before the cost gets away from you.

[@rickygurley6663]

Where is that located

[@sonarTM]

Interesting video. Definitely learned some valuable things. Thank you!

[@mikebrown5648]

I have tried everything on this motor Replaced everything three to four times this is the only thing I haven't done thanks for this information I will try this and report back

[@MultiDreamer1979]

Well come on what is it did you fix it bro I’ve been waiting for six months!

[@ericherrera6850]

Did it fix it ?

[@kevinerupp]

Fixed?

[@hondaxl250k0]

I’ve got a 4.3 in my gmc safari. Man it eats rotors. Bout every 3 months. It shorts out. I replaced everything I could. I’ve been a mechanic for 15 years. I gave up and just replace the dam 12$ part . Fixes it for a few months.., but other than that. It’s been a great van. About to hit 300000! No rebuild. And don’t drink oil. Although I’m a Lop user. Mainly the oil stabilizer..

[@daboo7725]

Use genuine GM cap / rotor,, the aftermarket ones are junk and act just as you described. Make sure your plugs and wires are in good shape as too hi a resistance there can cause the ignition coil to dump full voltage all the time and burn up caps and rotors like crazy. I'm a 35 year professional mechanic / shop owner. Been there done that as they say

[@ArtMonkey5150]

A labor of love. I have a Chevy S10 2.2 and it misfires. I paid $130.00 to have my spark plugs replaced and it's still doing the same misfire.

[@hudsonhawk0016]

It's the cheap plastic distributor housing causing the problem. The distributor shaft wobbles throwing the PO300 code. Replace it with an MSD distributor with an aluminum housing.

[@paulhammonds2932]

That's what I'm thinking. Mine got were it would not start at all.. Replaced distrubtor cap and rotor button. Ran great about a month.. Now it cuts out misfires

[@hudsonhawk0016]

@@paulhammonds2932 My 96 5.7 Vortec throws the P0300 code. They and the 4.3 are notorious for it.

[@markvest6442]

Thank you thank you...I think it was you.. DISTRIBUTOR CAP AND ROTOR got me....now she's running again and I'm a happy guy...thanks if that was you that replaced everything and it ended up being the distributor cap...saved my arse...

[@aronkoppold3981]

A complete accel aftermarket distributor is a good part for the 4.3

[@allentompkins4063]

THE EGR DOES NOT LEAN OUT THE MIXTURE ...The EGR valve richens the mixture....the EGR valve allows a precise quantity of exhaust gas to re-enter the intake the system, effectively changing the chemical makeup of the air entering the engine. With less oxygen, the mixture burns slower, lowering temperatures by almost 150°C, and reducing NOx production for a cleaner, more efficient exhaust.

[@mlp8500]

Hot shit u made my day same exact issue could not find nothing till I found ur video… thanx👍🏼..

[@GrantOakes]

I did the exact same things! I have finally replaced the EGR and tomorrow I'll know if that was the reason why it was throwing P0300 (random misfire) codes and the NOX emissions was failing.

[@Mike_The_Hog_A_Nator]

I've got 1 for ya. 02' Blazer 4.3 Zr2 4x4 2dr. Ran fine, stopped at store, got back in wouldn't start. Days later the Shop tells me they think the Coil Shorted out the ICM and they also put a new distributor, cap & rotor in. $700 later I pick it up & no power when it reaches Operation Temp. Fuel pressure good, shows a misfire code, replaced the plugs & wires myself. Also replaced the Coolant Temp. Sensor. Not sure wtf is going on! Taking it back to the shop, this truck was running perfect before it had a No Start Condition. I taken it to a few shops & they say it may be the plugs, or spider injectors. I don't smell fuel in my oil & remember, it ran absolutely fine, just had a no start issue. It has power when its cool but when it reaches Operation Temp? It just bogs down bad! In gear worse but in park also. Got me confused

[@AJ-cn1xy]

Your loss of power as your truck warms up sounds like what happened to my 2001 Blazer LT and my sisters 2002 S10, both were bad catalytic converters. I swore my transmission had gone out, nope.

[@Mike_The_Hog_A_Nator]

Yep, it was a clogged up cat! Got a new $80 Flowmaster Cat & she's running better than wife's new car & getting 2002 sticker mileage at 16 in town. She's running a tad warmer, but it's hot down here, S of Houston. It does fine in the mornings when it's cooler out, but when it gets hot outside. My temp runs around 210 or a tad past 210 if I'm towing a small 5x9 utility trailer. I guess with a 195 thermostat it's normal. No engine noises or coolant bubbling after I kill it. I've flushed the radiator twice & it wasn't bad, cleaned outside of my radiator, installed a new Hayden 2786 Severe Duty Clutch Fan & another 195 thermostat. No changes in temp after doing all of that. The only thing I haven't changed is my belt, tensioner & idler pulley

[@DragnDon]

Thank you for this video! Been wondering what was causing the misfire gremlin that was plaguing my 2000 Jimmy. I just took mine off, clean it, made sure the plunger was moving freely, and put it back. That seemed to have cleared up the issue. At least that part was nice and easy to get at :)

[@cliftonflynn337]

The cam positioning sensor underneath the distributor cap

[@brensdaman926]

I deleted the EGR, cat and smog pump on my Blazer. Runs a hell of a lot better. Always use ACDelco parts on these and you'll have a long lasting, smooth running 4.3

[@erikbarragan159]

How did you do that? Is there a video you recommend?

[@brensdaman926]

@@erikbarragan159 I don't think I watched any how-to videos. The EGR is on top and I just had to look up the smog pump location and it was pretty straight forward

[@dailys1979]

98 Sierra 4.3 280k miles. New plugs wires distributor fuel filter ect... the basics. Haven’t touched egr or maf but carefully cleaned maf. Bad misfire/sputter under light to moderate acceleration. Worse after it rains hard it seems for some reason. Cranks great idles great. Runs good under heavy to full throttle. Just bucks and sputters like crazy when accelerating normal. After warmed up. I mean after running for 30 plus minutes it gets better. The longer it runs the better it gets. But I rarely drive more than 10-15 minutes at a time. I can let it idle and warm up before driving for 20 mins and the issue may not be quite as bad but is still bad. The harder I drive it the better it runs. I’m lost on it

[@kvb_4117]

Mines the same exact issue. You ever figure it out?

[@AlexRides808]

Dammit. That's why I'm here

[@tjdjinn1983]

Yeap mine too unfortunately

[@jimmypatch5030]

I’ve been having these issues myself. It got to where it didn’t start at all. I bought a new cap and rotor and it ran fine for a few months then one morning after it rained it started missing and bucking on light acceleration. It pretty much goes away it I drive it 10-15 min and then let it Sit so I’m thinking there’s moisture Getting under the cap and once it gets to temp and Then sits it evaporates the moisture. If any of you guys figured out what kept causing yours please do tell!

[@juanesparza9197]

I got that same vehicle and same problem under light acceleration it jerks but when it warms up the problem is less noticeable

[@ginaboos9563]

Not all 4.3s have an egr valve. My 95 and 96 did. My 03 doesnt. Also ive cleaned them. Some carb spray and a little brush. Works for a while if its a carbon issue. Had a running rich problem turned out leaky evap and purge valve was sucking air. ALWAYS use oem fuel pump. The cheaper dist caps dont last as long as the copper/brass ones. If u have to replace injection spider get the updated one with the injectors on the ends not the poppet style.

[@u.s.a.198]

I have a 03 astro 4.3 Once a year I replace the distributor cap & rotor. And keep a cheap spare set in my van. Tried everything.. vent screens in and out, new distributor.. sealed around cap, dielectric grease inside etc.. nothing helped. I use the $60 Mallory or accell cap with $20 rotor. This cap has copper contacts. Seems to last longer

[@mikem5475]

Mine was plug wires!!! Spray water at night and look for the stray spark!!!

[@chicagorc3967]

please explain better? you had a broke wire?

[@mikem5475]

@@chicagorc3967 No, the spark plug wire insulation near the boot was touching the exhaust manifold, and over years it got hard and brittle and cracked. This allowed the spark to jump right onto the exhaust manifold before reaching the spark plug. I found out it was doing this by spraying water on all of the ignition components until I saw it arcing (lightning/sparks). You can hear it snapping/cracking too but my engine is too loud to hear the sound of the spark/static

[@jimmyhamm9737]

GREAT COLOR PAINT ; IT'S HARD TO FIND IN GREEN.

[@MrAgcano1]

Thanks Mr Posse rush for the video i think i have this problem i removed the oxigen sensor to do a back pressure test and after that my van stater running bad, astro van 4.3 troble code P0300 had replace all the parts you have on yours exep the fuel pump or rebuil engine.

[@vincewatson2569]

4.3 needs 65psi to start needs 52 to 60 to run

[@meatball4180]

Great video. Very educational.

[@lost_highway_guy]

Where is it located? From ur video it appears to be in the front of the engine, between the alternater and song pump , but it's not there on my 02. It's been in my family since new, so I know it's the original motor

[@Thundarr995]

Chilton's manual says fuel pressure is supposed to be 60-66 psi.

[@RaoulThomas007]

It depends if you have a TBI or a CPI engine.

[@cameron2807]

What does the owner manual say?

[@RedneckMechanicsYT]

I got a 2010 Silverado 4.3L. Having the same issues and past couple days it's really been a b***h to get up to speed now constantly. Runs great then misfires. Loses power slowly to almost none and then boom power...repeats several times. Hoping the egr is the issue. THIS IS THE ONLY VIDEO I CAME ACROSS WITH SOLUTIONS TO THIS PROBLEM. I bought the truck in January and started acting up a month after I bought it. Had a complete tune up right before I got it. Now...that all makes sense....

[@downsouth5014]

You ever figure out what it was I'm having a similar problem as you?

[@Mike_44]

My Dad's '03 BLazer 4.3L V6 has got a rough idle/misfire while on Drive, it doesn't happen while car is parked. Our mechanic changed the spider injectors twice, car has new spark plugs & new wires, he also tried another computer, nothing, then changed the dist. cap and rotor, checked the EGR valve.. nothing. Car still has the rough idle/ random misfire while idle. My Dad has spent a lot of time/money trying to fix it since it has such low mileage, only 74K miles for a 2003. I hate to get rid of it after all he's done.. What could be wrong with it? I wonder if it could be the first O2 sensor and replace the distributor cap/rotor with the Accel and/or AC Delco as you recommended see if that fixes the issue..

[@ginaboos9563]

Check for wires grounding out when u shift to drive.

[@Mike_44]

@@ginaboos9563 Thanks. Dad sold the car last year.

[@cliftonflynn337]

Cam positioning sensor underneath the distributor cap usually is the problem I found driver side plug to misfire

[@billyspray5357]

Have you ever had one run smooth accelerating and decelerating but skip when topped out?

[@billyspray5357]

What happened and what did you do?

[@donaldennis8218]

@@billyspray5357 mines doing the same thing did you figure out the problem with yours

[@tjdjinn1983]

I'm having this problem right now

[@kempaswe4022]

I will try this on my 97 blazer 4.3. The CO and CO2500 is way High, I have changed spark plugs etc.

[@hb5914]

What are the factory torque specifications for the EGR valve bolts? Thanks to anyone that answers my question!

[@DiegoGonzalez-dt4zt]

Ive been fighting a misfire on cylinder 5 for months now I’ve change fuel pump,wires,spark plugs, all injectors, distributor cap and rotor and nothing any help?

[@Nudnik1]

Check cylinder leak down for bad valve or spring or lifter worn

[@RaulRodriguez9mm]

Same

[@JoeShmo-r8v]

Could be bad coil or ICM

[@rickybearden4575]

i had the same problem replaced battery, alternator egr valve, new tune up, changed fuel fiter 02 sensor, and the maf sensor finally fixed it! makes you want to stick a mop handle in the dam gas tank light it and run like hell

[@jeffreyshumate370]

it doesn't have spider injection

[@GlynRobinson]

2003 S10 4.3L The P0300 will be the death of me! Will not set code if you keep engine RPM under 2K while driving.

[@cliftonflynn337]

Cake distributor cap off with t15 take rotary button off replace cam positioning sensor that will be your problem

[@dannymorgan6053]

good info but not all 4.3's have egr valves and still have gm engineered misfires. Vehicles from gm seem to be engineered for life of the warranty only!

[@aronkoppold3981]

Start with a brand new distributor and go from there

[@edrosa5079]

is there a newer motor i could put into my truck that might not have this issue

[@dannytreml3874]

I'm told it's spider injector

[@youngsinatra6504]

I put marvel mystery oil in My truck nd then changed my spark plug wires it is backfiring and I'm getting a multiple misfire code its a 4.3 it cuts off when I'm in reverse

[@cameronjackson3746]

i meed help truck cranks idles low 400rpm sounds horrible give gas boggs like it wants to die gets above 1100rpms runs perfextly fine

[@GRAVED1GGER44]

Same here. Did that for about two days. Now won't start. Cranks strong just won't fire up.

[@michaelknupp7425]

sounds like mine was told maf was bad replaced it run good for three days then rn bad again here had vacuum leek hose under air intake must have preesed it tight when did maf

[@Oxfire95965]

GM is really going down hill 2022

[@jamesfair9751]

Mine has random misfire code I changed plugs wires and distributor cap. I didn’t get accel or ac delco they didn’t have either in stock and the one I got was actually $2 more than the ac delco. Anyways it’s still running bad. Seems to idle fine. When you first take off it bucks and back fires then as you get going it’s fine but then when you level out and just hold the gas at say 55-60 mph you can feel it slightly bog and buck. If you give it gas it smooths out again. Very weird has anyone else had this similar and fixed it?

[@paulhammonds2932]

Replaced cap and r.b. on mine.ran fine for about a month.. I'm thinking distrubtor worn out.. Mine does the same as you're describing.. You figure yours out?

[@saltybuckeye]

Does it always throw a code for the EGR valve for the S10

[@hunterallen9739]

Not sure if I’ll get a reply but I put a new rotor button and distributor cap, plugs, and wires on and it’s running rlly rough before I even did this it had a little misfire but it ran great but now it’s so bad I don’t have any power

[@jayclark5912]

Crank sensor can rub on relutctor. Sometimes it just needs a shim. There's a TSB for it. Suprised this fella didn't mention it. Pulled my sensor and saw scratches on it as evidence it was rubbing. Narrowed it down with a multimeter and scam tool.

[@thedullone]

is that neighborhood dog still barking?

[@edrosa5079]

My mechanic says i need a new motor

[@samuelrosa3155]

Can the altitude change the performance of the truck, Florida to Lawton Oklahoma. Fl 200 ft Lawton 2000ft . Hope I did my research right

[@yucannthahvitt]

Yes. Air density is related to air pressure, higher altitude, lower air pressure. Lower air pressure (with similar temperature), lower air density. Lower air density, less power.

[@roadstar499]

I have a 2001 chevy blazer 4.3 v6 that has had the front Cat removed and the rear cat gutted? I have done everything to try to get it to run good put $$$ into it spider injectors, tune up, Maf sensor water pump,new distributor etc... I also have 02 sensors(have not installed yet) i bought since my code reader said bank one was bad . It still runs very rough I just want to get it running good sell... Any suggestions? Thanks for your time..

[@westside_tints8197]

Change the 02 sensors. I have an 01 blazer. Ran like crap until I changed the 02 sensor was dead smoothed out the misfires

[@roadstar499]

@@westside_tints8197 yes i changed one so far..will ge t the others tomorrow.. selling it after regardless of how it uns after... thanks for your input..

[@westside_tints8197]

No problem. There all turds lol

[@michaelroot6064]

Maybe mass airflow sensor

[@signedupfordoconly4275]

Maybe aliens. About as accurate as your suggestion.

[@michaelroot6064]

@@signedupfordoconly4275 how tall are you and how much do you weigh

[@silversurferhdz]

What color is the wire. I have no lettersm

[@williamcox2996]

why no gasket on EGR ? What year is this 4.3 ? 1996 ?

[@antonchigurh7279]

15 minutes of video I got 2 minutes of information and a lot of yada yada yada yada yada

[@jethro9341]

15 minutes and one second.

[@colecole3352]

Well go pay someone for info or stfu its free. How many hrs did he spend looking for something you had to watch for a few mins. Stop crying.

[@04DynaGlyde]

There's a few videos that say to clean the EGR valve after testing the plunger. Do you recommend it, or to replace it?

[@Bearcat870]

After market parts for Chevy blazers works fine.

[@nathanhale7444]

The older tbi 4.3s were way better. I think some Ford engineers hit jobs designing this crap for gm to sabotage them and this was the result. The 4.3 is a great motor otherwise.

[@paulbrantleylewis228]

Help

[@cliftonflynn337]

You guys can thank me later

[@TX_YUNG_GUN]

Not sure if I'm here to observe information that no one gives af about or just get to the point what is the issue 🤔 no wonder this guy has only 1k followers that explains everything. I'm off to the next video this guy reminds me of a operator 🤣😂🤣

[@aronkoppold3981]

The plastic one is a POS

[@yankeecanivers2654]

Just get to the point Buba

[@doodah2475]

Get to the point of the video

[@ieattacosforaliving341]

Bro hes listing off all the things that can go wrong or bad on the 4.3L and what everyone says about it that's most likely wrong. If you listen, it can maybe help you out.

[@saltybuckeye]

He did

[@brendawitt4826]

Hellow

[@davidsandoval8398]

Get to the point

[@seanhauser8228]

No shit! Literally a 15 minute video of how to check your egr valve with a volt meter , complete rambling

[@rorycrane1630]

If you’re going to post a video at least show what you’re doing while you’re talking. This was not any help at all

[@deanangel757]

After 3 minutes of you stumbling around and talking about what it isn't I lost patience because of the way you speak.

[@joehalliday4989]

3 minutes worth of knowledge and it took you 15 minutes nice video just you got to cut it down man we don't need all that