I kinda have a wierd one. I havn't even looked at this thing yet (my friend's car) 89 trans am 5.0 vin F. He says the car runs great when cold. Once the car warms up to 220, the idle fluctuates up and down, about 300-500rpm, and smokes. Rev it up blows smoke out like a big dog. Why the hell would it do it when warm only, I mean could they have hooked the egr up wrong? I know there should be no EGR at idle, the car has 90k miles on it and is fairly well maintained. Anybody ever hear of this before??
Thanks

 

That is usually a sign of worn pistons/piston rings etc. What colour is the smoke...white? black? blue?