Skip the auto shop - Our mechanics make house calls

Q: Misfire on cylinders 1&4

asked by on

Good afternoon

I am the owner of a c5 a6 2.7t, and am having misfire issues, even after already replacing all spark plugs and coils for cylinders 1&4.

After running VAG-COM, I got code's for: random misfire, misfire on cylinder 1, and misfire on cylinder 4. I've been researching and saw that people were recommending switching the connectors on the ignition control modules. I find it odd that after i cleared the codes, switched the connectors on the icm, and started the car again, cylinder 1 was no longer misfiring, just cylinder 4.

Background on the car: I've read that people were having issues with the coolant temperature sensor, but I had already replaced that part, and don't feel that to be the issue. I've also had the dreaded nightmare of having the transmission control module under the passenger seat get flooded. No need for concern though, it's dried out, and in working condition. The car was misfiring before the flooding happened, so that rules that out (I believe).

My car has 137000 miles.
My car has an automatic transmission.

It sounds like it could be the harness and simply disturbing it by swapping connectors eliminated cylinder #1 from misfiring, for now. Having owned a few VAG products and having many friends with them, you might want to try a coil conversion/ICM delete kit.

Enlist a certified mechanic, such as one from YourMechanic, if you need some help with getting this fixed. They will be able to diagnose your misfire firsthand and help you fix it accordingly. Good luck.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car starts and shuts off

Hello. If the engine only runs for a second and then turns off then that usually means that the engine was not timed right. You will need to remove the distributor and retime it. It can also be a defective...

Q: Damaged shock absorber - 2000 Isuzu

Hi, thanks for writing in. That is your steering stabilizer. This dampens any steering vibration, prevents your steering wheel from shaking while under normal driving conditions. If damaged you may lose steering all together. It is best to get this...

Q: Car shutting off

It is possible that you could be having an issue with your alternator. If your alternator is not functioning properly, all the electronics in your vehicle will run off the battery. If this happens, the battery will eventually die. I...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.