i have a 2002 oz rally with a turbo kit installed. there is a decent sized crack in the downpipe causing it to lose back pressure. i have a problem with occasional erratic idling and if u accelerate too quickly the motor sputters badly. i think this problem may be because of a dirty throttle body or a bad IAC. but the downpipe crack may be a part of it as well. please give me your thoughts on what this problem might be

 

it sounds more back pressure to me. our cars do have a problem with iac motors and is at least 350 from the dealer. i doubt that the tb is really that drty to cause any of your problems. the other thing i would look at is your throttle cable over top of the turbo mani. ive seen a few of those melt....


josh

 

I dont think the crack is causing anything although they have those exhaust fix strips you could buy and see if covering the crack helps. The only back pressure I have is the turbo, other than that I have full 3" straight pipe from the turbo back with no issues. I would check the normal tune up items along with your list of things.