throttle body cleaner does wonders. as for the k&n, it actually works. we have a dyno at school and they decided to do a test, same car both the drop in k&n, and the k&n intake set up. the drop in gained about 1 hp, i know not much at all but as long as you follow the instructions on the recharge kit. get this the whole assembly actually gained all of 2-4 hp. the instructors were saying the assembly's really wont do much for the price unless youre gonna do some major work. in my opinion, 300-400 dollars for 2-4 hp....it would be smart to just pass on it. but i did have a similair problem, i needed a new iac. it solved it, and price wasnt that bad, about 49 dollars.