Black 02

My '02 Z06 recently developed a really strong odor when driving. Smells like a bad exhaust leak inside but I haven't been able to find one anywhere in the system. When I switched axle backs the center two tips turned black very quickly, in less than 100 miles. The car sometimes dies at lower rpms and overall doesn't seem to drive as good as it used to before the weather warmed up. My friend was following me last night and said it was blowing white smoke when I got on the throttle.

The car has 111k miles and I installed a new cam, lifters, head gaskets, springs, valve seals, etc about 1000 miles ago. I had it tuned by a reputable local shop and these problems all developed when the weather got hot.

I pulled the battery cable to reset everything last weekend and it seemed better but came right back after about 20 minutes of driving.

I know white smoke usually means coolant, but I feel like the car is running super rich lately, with poor economy to go along with it. The rpms also like to hang when coming off the throttle or stopping at the light. I feel like a lot could be wrong. Any ideas where to start???

Black 02

Checked the coolant tonight and it wasn't low. The oil also smelled and appeared normal.

3sACROWD

The white smoke tells me you're burning coolant. It may not be bad enough to drop the levels yet. Try pulling the spark plugs. If one or several are really clean (like brand new), you have a coolant leak in that cylinder. Typically a coolant leak steam cleans the cylinder it is leaking into.

I don't know much about tuning but maybe your tuner needs to double check the tables to ensure he doesn't have it running too rich at lower speeds. I wonder if he was compensating for WOT conditions. Also check electrical and other connections at the MAF sensor. Just thought starters.