So I went out & bought a 1/2" copper cap & drilled a1/4" hole in it just to try it out since I seen it in a couple other threads. It works good my RPMs drop way faster & shifts are a lot smoother. But... when im cruising all of a sudden i hear a loud noise.. Like a loud cruise ship horn.. could it be that my IAC is bad?

 

yeah thatd be your iac sticking open and resonating some noise through your intake. ive literally had so many problems with my iac valve, i went through about 10 of them so far. i completely gave up and just blocked the whole thing off, kept it plugged in and simply adjusted my throttle body open enough for idle, and so far its been working perfectly fine. hopefully in your case you can cure it by just buying a new iac valve.

 

That IAC trick is a bandaid used to fix an actually problem, try replacing it.

 

lol wow well I really hope I dont have to go throught that many IACs. That just sounds like a hassle.
& I just thought id give this mod a shot just to see the difference I knew I was eventually gonna have to replace a senor or valves.

 

I've never heard of the mod myself.

Do you have a link or something that shows how to do this or basically what the purpose is?

Thanks!

 

Well theres two ways. theres a gasket and then theres the copper cap. All it does is limits the amount of air going through the iac when you let off the gas. From what ive seen so far most people use it because they have a high idle problem. But like uberstang1 said its just a bandaid..

This is the gasket type one:How To: IAC Rev Mod (Fixing the hanging RPMs)

This is the copper cap:Hanging RPM's When Coasting