Chuck-S4

I got this problem and would appreciate any help:

- Engine ignites / revs but on only 5 cylinders (sometime even 4!), runs horrible like a tractor, chokes and dies if you don't rev it, and then goes back to normal on 6 cylinders after a minute of mid-reving ; if you don't rev the car, the engine dies. If you throttle/rev so it stays between 2000 and 3000 rpm, then the problem disappear after approximately a minute, when the engine has the time to warm a bit. It runs smoothly after.
- Once in a while = Blinking Check Engine Light
- DTC = Random misfire, coilpack ... the usual suspects
- Coilpacks and plugs have been changed
- Problem occurs only when engine is cold;
- Problem occurs only when outdoor temperature goes near or under 35-40F (5 Celcius);
- Problem occurs only once in a while and randomly.


Any idea?

ykrboy

I have 08 Touareg with 3.6 VR6 and it does similar thing. When it's cold it sounds like it's choking and almost dies so I have to rev up rpms. After a min it's better. Check engine light is not on. I had bad pvc valve before but that's fixed now. New spark plugs. Not sure what else can cause this problem.

Avantthinking

Sounds like you may have a vacuum leak. A vacuum leak will causes the ecu to richen the fuel mixture which fouls the spark plugs. Once the engine warms up enough the plugs clear and misfires quit.

Aftershock2501

I have a 2009 a3 with a similar issue ive not been able to fix it but try starting the car then when it start turn it off again and then start it again and see if one the second start up it runs just as rough

Flybywire

Ignition coil packs are typical suspects and can easily be diagnosed by switching to another cylinder that is firing properly. Check ignition control module P/N 4A 090 535 1A. My B5S4 had a misfire in one of the cylinders and this was the cause. Be sure to replace both control modules since if one is bad, the second one will go out shortly.