Problem with cylinder 4. any help would be appreciated

[istaygold88]

recently got back from a trip to vegas and while driving back i noticed a slight miss fire nothing crazy so i jumped ahead and assumed coil packs may be bad and spark plugs..changed them today and actually swapped 4 to 5 and then back 5 to 4 and only miss firing cylinder 4 no other cylinder...im assuming the worst and thinking its my valve thats gone bad? anything that you guys would think that could be something else? fuel injectors?
any help would honestly be appreciated honestly...
almost forgot i put that solution into my gas tank that cleans up carbon build up so hoping that works?
what about sea foam? maybe that would help?
doing the compression test after I'm done with the carbon clean up liquid..almost forgot

summary

miss fire cylinder 4
new coil packs and spark plugs
still miss firing during WOT after replacement
only cylinder 4 though

[audis4noob]

I had misfire in cylinder #5 I re gaped plug and it fixed my problem.

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[istaygold88]

still learning lol.

you re gapped plug meaning?

sorry lol

[JVD]

Search spark plug gap.

Also, these cars get quiiiiite a bit more complex than spark plug gap. Keep that in mind before really diving in.

[vavJETTAw36]

recently got back from a trip to vegas and while driving back i noticed a slight miss fire nothing crazy so i jumped ahead and assumed coil packs may be bad and spark plugs..changed them today and actually swapped 4 to 5 and then back 5 to 4 and only miss firing cylinder 4 no other cylinder...im assuming the worst and thinking its my valve thats gone bad? anything that you guys would think that could be something else? fuel injectors?
any help would honestly be appreciated honestly...
almost forgot i put that solution into my gas tank that cleans up carbon build up so hoping that works?
what about sea foam? maybe that would help?
doing the compression test after I'm done with the carbon clean up liquid..almost forgot

summary

miss fire cylinder 4
new coil packs and spark plugs
still miss firing during WOT after replacement
only cylinder 4 though

Any codes saved in ecu?


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[LakeTahoeQuattr]

This exact thing happened to me last week. It was a ICM. Try swapping ICM cables from one bank to the other and see if the miss goes to cyl 1.

[MetalMan]

Can try swapping around cyl 4 fuel injector as well if ICM swap doesn't solve it.

[CJ_]

Compression test should tell you if a valve is bad.. Literally had the same thing happen on the way out to vegas last weekend. My thread is a few down from yours and has quite a bit of information/things you could try but mine ended up being a bad injector

[88ninety9]

Great info laid out right here. If you don't already have it, get vagcom. It's a necessity for owning vw cars

[MikeyB3]

What spark plugs are you running?

[istaygold88]

no codes showed up...was driving with the computer connected and watching the cylinders and 4 was the only one miss firing..then my check engine light would flash for a few seconds then disappear..

[istaygold88]

alright ill definitely try that..driving around right now to try and clean up what ever carbon build up i have and then compression test..if valves come back fine ill try it

[istaygold88]

stock spark plugs believe the ones NGK from ECS

[landfill]

Swap coils>ICM>plugs>injectors. After that it's
compression check and leakdown time. You can
check exhaust backpressure, cats, and other shit
but that would more than likely effect a whole bank
instead of one cylinder.

[2000s4_m]

recently got back from a trip to vegas and while driving back i noticed a slight miss fire nothing crazy so i jumped ahead and assumed coil packs may be bad and spark plugs..changed them today and actually swapped 4 to 5 and then back 5 to 4 and only miss firing cylinder 4 no other cylinder...im assuming the worst and thinking its my valve thats gone bad? anything that you guys would think that could be something else? fuel injectors?
any help would honestly be appreciated honestly...
almost forgot i put that solution into my gas tank that cleans up carbon build up so hoping that works?
what about sea foam? maybe that would help?
doing the compression test after I'm done with the carbon clean up liquid..almost forgot

summary

miss fire cylinder 4
new coil packs and spark plugs
still miss firing during WOT after replacement
only cylinder 4 though

You could have a vac leak, there is a vacuum hose near the throttle, check all the hoses near intake manifold

[istaygold88]

Swap coils>ICM>plugs>injectors. After that it's
compression check and leakdown time. You can
check exhaust backpressure, cats, and other shit
but that would more than likely effect a whole bank
instead of one cylinder.

gonna be doing the pressure test tomorrow to find out about the cylinders..after that we are doing icm and injectors. did the coil swap and spark plugs and still miss fired on cylinder 4

[88ninety9]

You could do icm's in a matter of 30 seconds, id do that before the compression test