Ok, my car has been plagued by idle problems for at least the last six months. The car idles at 2,000 rpms if it's moving faster than 1mph at all.. at a stop the thing idles at 1000 rpms (always has since the day I bought it). If I take it out of gear at 1500 rpms the thing will typically (but not always) climb up to 2000.. this gets old fast as the car is quite loud (3 inch dual straight pipes).

The other week I got a code 502 - it's an IAC code - unusually high idle or some such is what it says in the manual. The SES light has since shut off. I also noticed that the car makes a loud whistle also so I thought I may have a vaccum leak but it appears that that's just the alternator making noise. I did a vaccum test on the car today with a vaccum gauge - I hooked it up to one of the lines on the intake manifold and got a steady 21 inches of vaccum. So I have decided that the problem must be the IAC - I do not have a scan tool so I cannot check the IAC steps.. likewise I found it impossible to test the resistance of the IAC with a multimeter because GM put the thing in such a hard to reach place (f'ing ahole designers!!! )

So unless anyone has thinks I should do something other than replace the IAC I need to know how to get the dang thing out. I already pulled the alternator brace, TPS sensor, PCV hose, and some other tiny hard plastic hose that runs under the TB for more room. A T20 bit seems to fit but I wonder if a T25 bit would fit better - anyone know? I managed to get the top bolt off with a little work but I just don't see how to remove the bottom bolt.. someone tell me what the secret method/tool is (some GM designer deserves to have his member chewed off by wolves for this f'ing horrible design). I'd like to not have to remove the throttle body as I have limited tools here (at school).

I think I'd rather remove and reinstall the Hooker LT's than do this job! Oh, and how do I adjust the throttle stop screw (just in case the new IAC doesn't stop the car from idling at 1,000 rpms at a dead stop - I think this is a different unrelated problem since the car has always done this but the 2,000 rpm idle thing when rolling is relatively new..)

Thanks

 

I remove the whole tb from the manifold. Four bolts, a couple of wires, pvc line and the cable. This you give you a chance to clean the tb and the passages with carb cleaner. Put on a new gasket and your done. If you haven't done the tb bypass this is the perfect time to do this as well.

 

The only way to mess with the IAC is to remove the throttle body. Not hard at all. Messing with the throttle stop won't really do anything for you (unless needed because of an aftermarket TB or some other extensive mods). The IAC will compensate.

 

Did this fix your high idle problem?