Sir Shnike

My 30v engine has a misfire problem in the cold weather (we're talking -20 deg Celsius). Misfires on several cylinders, but 99% of the time it's on cylinder 2. Funny thing is that the first I tried, the car misfired continuously and then I tried it a couple of hours later (so the engine was pretty cold) and the car ran perfectly.

I've changed the plugs (and tried swapping the cables). Also, I had the injector for cyclinder 2 replaced. So is it possible that the ignition coil for the V6 engine is starting to fail? Could a bad o2 sensor cause this? (I'm fairly at least one one of the pre-cat sensors needs to be replaced). Anything else that could be causing this intermittent misfiring problem?

Thanks.

Pat

A couple of us are having similar issues on the 1.8T. We're guessing coilpacks. Anyone else know?

Sir Shnike

I'm wondering if a block heater might help.

Shard7

The 30V has 3 coils, and each one is shared by two cylinders on opposite banks (both plugs fire every time, but the one cylinder is in its exhaust/intake stroke so it doesn't care). If a coil was going bad, two of cylinders would exhibit a similar problem (unless it's one of the two connectors on the coil that's to blame).

A bad O2 sensor would also affect more than one cylinder (all three on the same bank).

I'd recommend trying a general tune-up to see if that helps. Seafoam treatment on the intake and the gas should help to clear any deposits, and it's probably worthwhile replacing the ignition wires given the age of the car.

Sir Shnike

Good info on the ignition coil -- thanks