mine was playing up, cost me $7.50 to fix and about 3hrs but only 15min real work, kept playing with stuff.
i jsut pulled mine out and sprayed it with carby cleaner. works PERFECT now.
but before the car ran like a dog, then it got a little better but kept acting strange, so i gave it a squirt and all this black carbon crap came out.
give it a try, u might save yaself a few hundred.
i used CARBY & THROTTLE BODY CLEANER.