P0304 Explained - Cylinder 4 Misfire (Simple Fix)

[@johnrperry5897]

Finally a car tutorial that doesn't have background sounds burying the speakers voice. Or start with a 5 minute story about how they found out they had a problem.

[@simeonatanasov8421]

But is one that literally just covers the duh answer what google would say. Pretty poor video in terms of not including a lot of different things that could and do trigger p0304

[@stevenshackelford1937]

This guy needs his OWN You Tube Channel on fixing cars!! This graphical, easy to understand, rational step by step video is a 5 STAR all the way. TY soooo very much!!

[@hvacr24]

Before you pull the spark plug make sure you blow WITH COMPRESSED AIR, the area around the spark plug so dirt and debris does not fall into the hole...prep is EVERYTHING

[@paultavres9830]

I you had a vacuums leak on intake wouldnt you get a lean mixture code on multiple cylinders If it was the fuel filter wouldnt all cylinders be miss firing and running lean Worn spark plug what do they wear on Most plugs these good are good for 100,000 miles

[@kevinperry5672]

Also, check your sensor harness wires to see if they are frayed or chewed by rodents. I discovered a chipmunk or squirrel was bringing acorns into my engine and feasting on them and my wiring harnesses. They chewed through the rubber that protects the wires so I'm sure the bare wires were arching and causing the sensors to fail. Just a thought...

[@HardWhereHero]

I'm going to bang my head off the wall. I've been working on a 2004 GLS VW Jetta with a 2.0 automatic transmission. I FOR THE LIFE OF ME cannot figure out this random misfiring on cylinder 4. New coils, plugs and plug wires. A good friend suggested a compression issue or head gasket problem. Nothing there either. I'm going to check the fuel systems next because it's getting the correct air mix. I just drove it and noticed that the car backfires and runs rich. The backfires take place when going up and down a hill and combusting close to the cat. 😮 This is my daily driver and I'm trying my best to get this sorted on a very limited budget. I have all the tools a person could ask for but limited time and finds.

[@you_dont_wanna_know1969]

How did it go? What was the problem?

[@lydiavasquez1844]

I have a ford van v8 engine. bought 8 coils for little over 100 and spark plugs from oriellys for 6.00 each and 8 fuel injectors from geek parts online for 105.00. Hired a mobile mechanic off of Craigslist who charged me 150.00 in Oxnard. If I was in San Diego I would have drove it across to Mexico where the service would be less.

[@____unknown3137]

Sounds like a average tuneup labor price that was to much for u?

[@alfredweaver5390]

I have done a complete tune up and I don’t hear any air hissing any where but I still keep getting P0303 & 4. What else could be wrong?

[@illiest402]

Have you got the issue fix ? If not are you still driving it

[@rogerleadbeter1625]

2006 chevy cobalt 2.2. Replaced fuel injectors replaced coil pack replaced ignition module replaced spark plugs still getting misfire cyl 4

[@iSmokedutchh]

You probably have more serious problems in engine. Swap it

[@abramporras7877]

What was it

[@rogerleadbeter1625]

@@abramporras7877 bad aftermarket ignition module went oem as well with all components misfire cleared up

[@abramporras7877]

@@rogerleadbeter1625 thanx man no one ever responds on these 😂 appreciate it

[@rogerleadbeter1625]

@@abramporras7877 your welcome

[@tarrantking289]

Lol, i have this code and brought my 2019 grand caravan to the dealership to do a more comprehensive diagnosis... they said to replace all the coils and plugs (just to be on the safe side) and are charging me $500 JUST FOR THE PARTS (6 coils and 6 plugs) and then $700 FOR LABOR!!!! WTF!!! Well, I told then no... replaced everything myself for just under $200 for the parts. Problem is, the same cylinder is STILL misfiring... Anyone have another possible solution?

[@roadstar499]

Many other causes..injector could be dirty

[@Kasie.Mckenzie]

Hi I got a question I got a 2010 Honda Odyssey and the code po304 popped up as the four cylinder misfire and I changed the spark plugs I put in fuel cleaner and my vehicle when I accelerate really hard will start to jerk I checked the coils and they look brand new I went to Honda and they said it could be my off brand coils what is going on with my vehicle?

[@davidkaufman250]

Vacuum leaks now create a rich mixture? V4? This guy is a great actor, but doesn't know much about cars 🙂

[@watsonanthony8438]

Depends where the vacuum leak is at. My mustang had both lean and rich

[@SwooshSavvy]

Help! I got this code on my v6 mustang and already got new coils , spark plugs and wires and still not fixed . Even did a compression check and switched it around and it keeps coming back as a misfire on cylinder 4. What’s the issue then? Fuel injector? Is that the $700 fix ? ):

[@Sheevness]

Did you get it figured out? Fuel injectors can be fairly straight forward to replace.

[@SwooshSavvy]

@@Sheevness somewhat irony ce light comes and goes now sadly

[@MrMyreese]

Excellent explanation! I found the video to be very helpful. Thank you!

[@joedivincenzo2099]

question, I replaced all plugs and cyl-4 coil, I cleared code ( my scanner said "erase fail") , engine light went out BUT I still have a "pending" P0304 !!! Will that disappear after a while??????

[@Steve-og3cr]

Careful, you can only swap coils if they are "on plug" coils. If you have a coil pack, do NOT try that.

[@chuckpotts458]

how can you tell the difference?

[@Steve-og3cr]

@@chuckpotts458 a coil pack is basically a "box" of all coils in one, with normal small plug wires going to the plugs. If you swap the wires themselves you'll change the firing order. The animation here, shows the individual coils that sit literally on top of the spark plug. Then small gauge clips plug into them. As long as you keep the clip/cable in the same spot, you can move the coils around to see if one is bad.

[@All_praise4Allah]

Ive been doing it for years. Its simple. 1:un bolt coil pack 2:un plug the 'sus' coil pack 3:repeat 1&2 on a different coil pack 4:switch them, plug them in bolt them down. And re scan, if the 'sus' coil pack carries the code to the other cylander then it is the coil pack. If not then it is most likely the spark plug. If one plug is bad replace it and see if code clears. BE SURE to check for oil on the plug. If there is, you should replace valve cover gasket, and seals. " Recommend replace all spark plugs if you can" You can also remove the coil pack and use a multi meter to test the resistance, if you have one and know how to use it.

[@Steve-og3cr]

@@All_praise4Allah you are explaining correctly for a "coil on plug" type. I mentioned coil packs, I should have said ignition coil pack or ignition block to be proper. You cannot move the packs in those types. If you switch spark plug wires around it will be big trouble.

[@All_praise4Allah]

@@Steve-og3cr i know how to seperate the wires

[@froggerraver]

Watching this video got me to subscribe love how you break it down n fixes to a probable solution

[@fixdapp]

That makes our day to hear, James! Thank you so much for the kind words and subscribing. 😊🙌

[@Aero_HER_Dynamic]

Was getting p0300 and p0449 (vent solenoid). Changed plugs n wires...p0300 went away. P0304 comes up now and I haven’t changed the vent solenoid. My truck when stopped is shaking and running rough. Will the vent solenoid throw the p0304 code since it deals with air and fuel???

[@brother_jaha]

Did it? I think it would, you must have the answer by now

[@a1r592]

I'd like to add to at least check if the ignition coil is fitted properly

[@fixdapp]

Good point! Thanks!

[@JeriDro]

ignore the ratings on shops, I've been screwed by "5 star" shops many times

[@johnalvarez3307]

You should be proud...i don't even know how many stars was mine....ja!

[@Windsongpony]

I was told I needed a new head gasket?

[@Gooddaysalways]

I’m happy I found this video. I was totally freakin’ out!

[@fixdapp]

So glad we could help give you peace of mind, Kali!

[@alanspring8462]

One word vague

[@crazystax1]

should I change both plugs in 4th cylinder...or just 1. my code said #4 cylinder &coil

[@manueljuarez5314]

Coil pack

[@carsonbushnell8244]

often poor exhaust or cat can pull a P0304 too

[@johnboswald6049]

I’m getting that code , and the exhaust is in a bit of rough shape. That’s something I should check out your saying ?

[@davepersonal9082]

At :52 -- ...."unless your car was made before 1980 or if you have a dirtbike...you have a 4 stroke...." ?? LOL I hope this was a joke --- ??

[@skyforge]

Mine cylinder 4 misfire was caused by my 02 censors on my exhaust. I just replaced the censors and converter myself

[@callaedwards9184]

totally 'fixd' my car dude. thx

[@fixdaccount1714]

No Problem!

[@beastlychase]

Shit I wish it would fixd mine

[@hariszhr]

The prices mentioned in this video are way out of normal range. E.g., Spark plugs shouldn't cost you more than 10-15 bucks.

[@Perurikun]

doesn't that cost depend on the vehicle tho? the spark plug for a Corolla isn't gonna cost the same as one for a BMW.

[@jonathondenver9586]

Coil,both plugs,new wires,new injector,still P0304 cyl. 4 misfire,no matter brand of parts,changed twice,has all factory in it now,still misfire cyl. 4...cam lobe? Valve? Rings on piston? Does puff a little smoke when idles for 10 minutes and not drove,you drive the vehicle smoking out tailpipe stops

[@enobishop1419]

I have done everything I could ... maybe it's a vacuum leak or a fuel injector? ... it only runs ruff in slow idle and now most of the time Here is what I do do already which all helped and then problem still there Replaced: spark plugs Coils Mass air flow sensor Two solenoids Two position sensors Both oxygen sensors The fuel filter ( a little intimidating but done) Gaskets for valve cover Purge vale Another crankcase sensor under car Oil change I did clean #4 fuel injector - I hope it just needs a new one ? I'm running out of patience really but I am going to fix it Knowing quite well it's all part of planned obsolescence! It's designed to fail so all the parts eventually need replacement- it really sucks! It seems the sensors work together all right and all effects the other but never specifically Anyway- funny how it's the computer that's in charge not the mechanical parts that would run in older cars It line when AI says it's good - pay to have it scanned for smog check... ext It's frustrating!

[@VIIGerman]

So I bought this old beater sentra, and I got this error, as somebody who is new into the scene of DIY, your video saved me a shop visit and a possible pricey fix when all I had to do was switch 3 and 4, that worked wonderfully, THANK YOU SO MUCH!

[@fixdapp]

Excellent! Glad it could help!

[@brianhubbard799]

Is it cylinder #4 or #4 in firing order

[@TheLarryBrown]

It's cylinder #4, but anyway it's the same even if it's the firing order. Firing order is expressed something like 1-4-3-2. No one thinks of that as "cylinder 2 is the fourth to fire."

[@thehoodcleaners8426]

600 for a fuel injector were is this at ?

[@gabepetro358]

Yeah idk about that. But my honda odyssey has 6 injectors and they are $40 each though.

[@sydc4703]

I had done all of these and my car is still misfiring on cyilnder 4. I also did a couple of other things.. starting to think I have a bad ecu

[@JuanPerez-mk2ie]

Me too did everything have a 5.3 vortec

[@JuanPerez-mk2ie]

Have you fixed it yet ?

[@sydc4703]

No my next guess is to try a running compression test.

[@leeadams9004]

Did you ever fix your problem because I’m having the same problem and I tried everything

[@sydc4703]

@@leeadams9004 I just sold the stupid car lmao

[@chunkmonk]

thanks James Franco 😊

[@lindaclements8025]

getting p0304 in my northstar v8. hope its just the Splug or wire.

[@JeriGavette]

I bought a 2003 F150 XLT a week ago. I put some gas in it today & some *STP* - *High Mileage - Complete Fuel System Cleaner* in it with the gas. Right after that, I started the truck up & immediately the CHECK ENGINE SOON light came on & it feels like someone had pulled the timing completely out of it!! Its has ran great all week! Is this because of the STP I pit into the gas tank? (It was my 1st thought!) I am a female & just thought I'd start searching what the problem might be, as I am not a mechanic). The guys at the Auto Store recommended I put it in the truck when I put the gas into the tank. Thanks for this video. Not to find out how many cylinders this truck has!! Ugh... JG

[@MAWTech]

This guy needs to distance himself from FIXD.

[@ffas23]

Just got the PO 304 Code in my Wife’s 2016 Chevy Malibu 1.5T engine the other morning. I left the car running and opened the hood to do a visual and didn’t notice really anything out of the ordinary until I decided to unscrew the oil cap from the Valve Cover. When I did I could see some blow-by smoke coming out of it at the valve cover with oil cap off. At this point before I do anything I am curious to what you think? I can go in very easily and swap coils with number 3 and 4 cylinder to see if the number 4 coil is bad or not but in the back of my mind is the Blow-by smoke coming from the valve cover. The motor only has 35k miles on it. Can a bad coil cause the blow-by I am seeing? We haven’t driven the car since I scanned the car with my OBD II Scanner Friday morning. It is very early Monday morning right now. I made calls to the GM dealer Friday afternoon where I purchased the car from 6 years ago as a left over in February of 2017 to see if there was any power train warranty left on the car and was told no there wasn’t just in case it is a big problem internally. I have seen another You Tube video a Repair Shop did on another 2016 Malibu with the same 1.5T 4 cyl engine with a PO 301 Code showing Cylinder number 1 with a Misfire they claim has a bad piston. That engine although much louder in the video is also blowing smoke out of the valve cover. I really don’t know what to do at this point in time. In need of some help as to what to do next.

[@Gerry-xc2xo]

Use to run. Changed plug 4 then it would not start anymore

[@ferdinantkoci9385]

hello I have an opel zafira c 2013 1.6 petrol is idle while walking today it has ruined my work and it has this code p0302.p0301 what should I do who gives me a solution for this problem I have only changed the spark plugs

[@ricardoweis342]

Have DTC P0304 on a Chrysler Grand Town & Country 3.8 2011, have new sparks, new and OEM coil pack, new wires, tested and cleaned inyectors, no vacuum leak and DTC P0300, and P0304 they did not want to leave the chat, I hear a hydraulic valve lifter sound when the engine is running, could a faulty hydraulic valve lifter cause this DTC??

[@gclark5914]

I don't know when you will get this message but I have a Hyundai Genesis 2011 2.0 coils are okay spark plugs are new 1 2 3 cylinder works for is not no power through the wires that's where I'm stumped if you can get back to me and give me some tips be much appreciated how I know it's not firing cuz I put spark plug in the boot I'm turned on the ignition I no spark there's a spark plug as I say it's not my coils it seems to be the wire connecting choose a boot that's not giving power happened one day when I was driving on the highway

[@yeahrightmate]

A fuel filter would not cause a misfire on just one cylinder, and not any engine can swap coils, only ones with single coils per plug.

[@wht240sxka]

You forgot to mention that compression could be low on that cylinder

[@carsonbushnell8244]

did he just say v4 lol

[@LordBLocKeN]

lol i literally paused it there to hit the comments

[@ericlopez8744]

I think he doesn't really know alot

[@deuce763]

I had to replay too... lol

[@born2bdrunk41412]

Kevin Robinson same here lol

[@JM-nh8yp]

Yes. V4 engines do exist. Not as common as inline 4 cylinder engines. So the LOL is on you. Haha

[@alfonsosolano2089]

Does anyone know if changing spark plugs and/or coils to try to resolve issue voids drive train warranty?

[@mrbull213]

my 2011 e 2500. its naturalgas NOT GASOLINE and its low I wonder if its causing the problem because its low in natural gas

[@oatmeal7]

labor $40 to $70 for coil replacement. LMAO

[@rolandobaluyot3315]

i need how to replace it not your explantiopn of thge theory

[@Gabrito74]

Thank you saved me lots of stress!

[@fixdapp]

Happy to help, Gabe 😊 Happy and safe driving!

[@craigevans5120]

Great video and explanation. Thank you.

[@fixdapp]

Happy to help!

[@meshal_1179]

I have a 5.3 chevorlet Tahoe and the fourth cylinder isn’t working can you please give me a solution I don’t want to get a new engine

[@chrishulkow4171]

1 coil for my truck is 45 to 55 .. not 240 to 340.. per coil .. if i buy all 8 MSD coil from jegs for 280ish

[@roe2123]

Great video. Love the animations.

[@fixdapp]

Glad you like them! Thanks for watching.

[@FreshAsFxck]

Recap - just throw parts at it instead of performing diagnostic work. Smh

[@DSquire10]

Or, educate yourself about what the cause of the issue might be, and try replacing some parts yourself before taking it somewhere and spending a ton of money on a shop repair.

[@FreshAsFxck]

@@DSquire10 riiiight... OR you could do some actual diagnostics by doing various tests to determine what the problem actually is. Rather than just blindly throwing money and parts at it like 95% of people out there.

[@cfsouthern]

@@FreshAsFxck bro let me know how to diagnostically check my car I get the same code

[@truth2power463]

Gret advice on testing the ignition coil by swapping it out. It worked! Thanks so much.

[@bigcartoonyIIV]

I changed my silverado fuel injectors, It had a hard start, and when I pulled the old spider injectors out one was broken and oil and fuel was all over in my upper intake. FF I put everything back together, and now its running terrible. I brought it to autozone and the codes read misfire in cyl 4, fuel injectors , mass air flow, etc. My truck was working better with broken injector, than now. I dont know if the stiff line fuelinjectors bad, bad spark plugs, mass flow or whats the issue. any idea?

[@gabrielavega91]

Ugh I feel you. What was the issue

[@bigcartoonyIIV]

@@gabrielavega91 the FI hose was kinked. However Im back to square 1, because its back hard starting, and sometimes it doesnt start at all. Im thinking the brand new spider is defective

[@KishBish]

​@@bigcartoonyIIV did you ever get it sorted??

[@bigcartoonyIIV]

@@KishBish Yea it was the distributor cap, and a bad fuel injector. Now my battery is dead and on a flat..lol Im 2 steps from retiring that truck..lol

[@democratssuxmaga7965]

Ive changed, plugs, wires , coils, fuel filter, swapped injectors, checked fuel filter, vacum hoses and I still get an intermittent code P0304 and it usually happens after start for no reason.. car runs fine..Im thinking maybe the ECU...

[@LittleCoyot]

Mine started after switching out my downstream 02 sensor

[@strongebow]

Can it be water in gaz ?or it will p03XX on all cylinder ? happen to me 1 day after i fuel in cheap gaz place. Changed my spark plug and fixed it for a day and not it is back, my engine shaking p0304. It like random. Got white smoke at the exaust and stop to smoke after 10 minutes idle. Now raining outside and got the shaking back.

[@ernestogarcia6928]

I got the same problem, do you already fix it?

[@beammeupscotty2401]

I got fault code p301 and p304 .😢

[@acid2824]

V4 Engine Boys

[@7249xxl]

Lmao 4 coils plus plugs cost 100 euros for vwpolo

[@aniqcubacubajer2074]

I have a misfire cylinder 4 cylinder 3 cylinder 1 , on chevrolet cruze

[@skyledanguj6844]

I didnt catch how to find out which cylinder is 4th ?

[@serious_biz]

Depends on your make and model. Google "(your car make and model) firing order" to find out which cylinder is C4

[@robleslily98]

I just got this code on my 2010 Jeep Wrangler Sport unlimited. Came on when Jeep was in park at an idle. Any suggestions ? Code P0304. Cylinder 4 misfire. Thank you!

[@mayken6661]

Check number 4 plug

[@bobsmooth1739]

Excellent video, thanks for great content.

[@granderondeproductions3286]

I have a 5 cylinder straight engine. so lol I don't have a v-configuration. just a slight thing I noticed. but good info because, I had already replaced the spark plug and ignition coil.

[@sub1maz2]

Informative ... and funny

[@Gerry-xc2xo]

Lots of oil in plug socket holes

[@danieledamiani2250]

Since cylinders are sparked at a 1-3-4-2 sequence is it correct to swap them? I have a Vw Golf 6 that is misfiring on cylinder 1 and 4. The ignition coil is one tower (are not individual). Can I plug Ignition A to any cylinder different from 1? Wouldn't mess up the sequence of the crankshaft? Actually is not a COP Coil-on-plug but is wired (Damn it Vw!!) and every cable is different length purposely to reach the specific cylinder.

[@perlapacheco5515]

Thank you. You are wonderful!

[@haleymarie9839]

I need help my car says it has a cylinder 4 misfire . The problem is that the car starts but then looses power and dies . Please and thank you

[@guttaboykey8387]

Spark Plug and Coil Check.

[@johnnyortiz9146]

Did you say a V4 engine lol

[@ernestomoreno2596]

Do they sale a single coil on auto parts store?

[@jasonnorrie3834]

Yes O’Reilly just quoted me for one $75

[@Motionpressure]

What about a 5 cylinder?

[@EmeraldView]

Fuck cylinder 5. We're talking about Cylinder 4. Why does EVERYTHING have to be about Cylinder 5 with you?

[@da9thwondercwb96]

Lmao 🤣 🤣 🤣 🤣

[@MrTruckerf]

@@EmeraldView HAHA!

[@ukendtbro9931]

Hey, i double decat my car with a 3” Downpipe and then this code came “ P0304 cylinder 4 misfiring “ can u help here? My spark plugs are new and so are my coil pack

[@AlexCruz-et7rd]

Did you ever fixed the problem? I changed spark plugs, coils, and fuel injectors. Code still appears.

[@Gerry-xc2xo]

2004 4 cyl. 2.3L

[@LemonsCraftMC_GAMING]

V4 engine? Not a thing

[@Indi_DevJames]

This is so backwards for the Nissan plugs 20 dollers for some nice ones (under ignition coil) ignition coils are 25 bucks for a lifetime warranty ahah so cheap

[@Fan_Made_Videos]

Same with my Toyota. But then again, BMWs and Mercedes can cost $400 just to change the oil.

[@gabepetro358]

Honda has to take Ngk plugs. Around $15-20 each. I have an odyssey so I need 6. However the coils are $40 each.

[@paulcolletta859]

Thank you this video helped me very much

[@codyitalia8396]

In a v4 engine? Uhhhh

[@icecat2009]

Could an oxygen sensor or a catalytic converter cause a P0304 code?

[@apapz3245]

Yes

[@drkmagneto]

Cool video! Thanks!

[@davidneeson4922]

hey fixd im having problems with my seat cupra 2008 1p model. its saying multiple radom missfires, miss fire in cylinder 3. ive tried changing coils to see if the problem would change cylinder and it hasnt. so i decided to buy 4 new ngk sparkplugs and the problem is still there.. what else can i try as im really starting to get tired of this problem.

[@gabrielavega91]

What was the problem

[@paulcolletta859]

Thank you this video helped me

[@joereyna7704]

what if it says misfire on 1 2 3 & 4 cylinder code PO301, PO302, PO303 & PO304

[@gabe3599]

Rip

[@brianhubbard799]

Jack up radiator cap drive new car underneath install cap. Jk.

[@lacuevadeadulam]

V4 engine?🤦‍♂️

[@musicmancecuador]

Goog explained

[@flakomzr2113]

V4....

[@xGamingWithJasonx]

I ran my obd2 scanner and got a cylinder #4 p0304 code then changed all my spark plugs to,new Champion Plugs and now I'm,getting a p0300 code where multiple engine misfire I do have 4 o2 sensors that are failed could this cause the random misfiring.

[@arielzambada9911]

Your o2 sensors read how much fuel is been burned so if they are failed mean ur computer is dumping fuel into it and reducing it drastically on points wich can lead to engine failure

[@xGamingWithJasonx]

@@arielzambada9911 yes but my question is could the bad o2 sensors be causing the misfire noone ever states this in videos if bad o2 sensors can cause engine stalling/ rough idle

[@simar98]

can you drive your car if obd shows no4. misfire ?

[@Ronaldothegoat7841]

No

[@MrTruckerf]

Yes.

[@TheLarryBrown]

No. A misfire is a serious problem and will cause the car to run rough. You need to get it fixed right away and don't drive the car with a misfire. You should have it towed to a service center and fixed. Typically a car with a misfire has a large loss of power, so you don't want to drive that anyway. A misfire is throwing, at least a little, unburnt fuel through your catalytic converter, damaging it, and you don't want that.

[@freedompioneer4311]

@@TheLarryBrown my 2008 Honda accord EX-L V6 sedan Looks like the previous owner has installed as installed a spark plug with epoxy. My car started running rough and now it is throwing the P0304 cylinder for miss fire code. I'm pretty sure I just need to change all the plugs and quarterpacks but the spark plugs are oil fouled and and I guess autozone suggests I replace the mass air flow sensor too

[@TheLarryBrown]

@@freedompioneer4311 Spark plugs fouled with oil indicates some serious problem, are you sure about that? To see 6 spark plugs fouled with oil seems extremely unexpected. If it's just the top of the plugs, the part with the white insulator, then you may have a leaky valve cover gasket, a relatively minor problem and easy fix. If it's the actual plug, the bottom part that sits inside the cylinder, then you're sucking oil into the intake manifold and the car would be smoking like a mofo, possibly through a blown EGR valve...my Beemers can do that. If you are getting oil into the intake, replacing plugs and wires and mass airflow sensor is going to do little/no good and the plugs will just get fouled again. Anyway, everyone always suspects the mass airflow sensor but there are plenty of other places you can get problems. If you are going to change the plugs, do that first and see if your problems go away before doing the mass airflow. Anyway if you are only showing a misfire on #4 that does not lend suspicion to the mass air flow nor any problems outside of cylinder four. If you aere only getting misfire on #4, trade the plugs and wires and ignition coil between #4 and some other cylinder and you may see the misfire follow those #4 components. If you put the #4 plug on #3 and then #3 continues to work ok, you know that plug is ok. Finally, in the spirit of "test, don't guess," try to test the mass airflow sensor and observe faulty behavior before you just needlessly buy a new one.

[@0123Ricky]

Or inline 5 cylinder

[@cecigalvez630]

We have a grand Jeep Cherokee showing p0304. We changed the coil pack (#4), spark plugs, and gaskets, but still it’s showing p0304.

[@haydenstewart7079]

I have the same issue. Audi A4, p0304, new spark plugs in all four, 4 new coil packs, 4 new fuel injectors, only about a week later and the check engine misfire came back on.

[@MrUnknown747]

Did you solve the problem? My is250 cylinder 4 is missfiring. Coil and sparkplug not the issue

[@cecigalvez630]

So today we found out that somebody put coke in our gas tank. Fuel injector wouldn’t open up, our mechanic found sugar.

[@haydenstewart7079]

@@cecigalvez630 wow. What jerks. Can anything be done?

[@CashApp-HelpMeStayAlive]

@@cecigalvez630 Did you sleep with someones man ? Lmao. Why would anyone do that .

[@stephensneddon1059]

Great explanation...p0304 code came up...looked at the spark plugs first (number 4 looked worse)...changed them all.... fingers crossed that's the problem solved 🤞🏻

[@batuza4117]

Is the problem solved?

[@stephensneddon1059]

@@batuza4117 yes... problem solve....if it wasn't....it would of been replacing the coil pack, them MAF sensor

[@MJ.401]

I had all my spark plugs switched out, after p0304 code. A week later check engine popped back up, called mechanic they said it might just be cold out, i dunno

[@illiest402]

Did it work or was it just cold

[@jennifernoriega838]

​@MJ.401 same code on a 2022 vehicle with 80k miles I drive spirited changed spark plugs went away 2 weeks later cylinder 4 was misfiring might clean out coils before I buy new ones hopefully that helps.

[@edrobert5242]

Hi I got one Subaru wrx misfire 1 2 4 why it’s