kriwia

Hello, 3.2FSI engine cylinder 5 misfire showing on UBD check, engine running rough. Replaced coil and spark plug, car was running fine and after a week same thing happened with cylinder 5. Replaced all coils and spark plugs, the car was running perfect for 3000km and after 2months again cylinder 5 misfire. Replaced the coil and spark pug, done vacuum sea foam engine treatment. And after a week the same thing happens again. Can someone help!

eazy211187

What the mileage? What type of service has the car had done? So you replace all the the vacuum? or check them all?
What's the code for the misfire?

newa6er

like easy says, check the vacuum lines, also the fuel injector
if those dont fix it, have a leak down test done on that cyclinder

kriwia

Hello thanks for reply, car has only 75000 km, full service was done by Audi dealership 4 months ago. What is involved in replacing vacuum and what it is? Paid over $2k for the last service and I know they will take me for a ride if I drop the car to them. It could be something minor like electrical connection because when I tapped the top of coil a few times with small hammer the car started idling way better with CEL light off and the light came back on after a few minutes idle .

kriwia

I don't think it is injector because when I change coil the car runs fine for a day or so. Might have to a leak down test can that be done easily or by dealership only?

eazy211187

Have you check the plug itself?

kriwia

Yes, all new plugs, coils (latest update) and the engine still running rough. Will check the injector next maybe 98 octane fuel is too rich? Maybe should try 95 or 91?. Such a low milleage and problems like that.

kriwia

Are the vacuum lines separate for each cylinder? How do you check them? I am in Australia, warm climate and dealer told me the cars do not have carbon build up problems here. Car has a low milleage.