This used to only happen at stoplights but now it happens every time i let off the gas while driving. The idle wont drop back down when i let off. If i quick tap the gas the idel drops. Im assuming my IAC is hanging open. IS there a way to clean it out or fix it, or do I have to buy a new IAC? Thanks.

 

88,

Tapping the throttle won't affect the IAC. It is more likely that the TPS is getting a "dead" spot, your throttle cable is unwinding and sticking in its housing, or the throttle plates are mechanically sticking in the bores and binding in a partially open position. Remove teh throttle cables from the belcrank and test how smoothly they operate. While they are off, test the operation of the throttle body. If you can get it so stick open, you need to do some more work there.

Clean the throttle body and inspect the alignment of the plates. If the throttle shaft bushings are worn, there isn't much you can do other than to replace the bushings, since realigning the plates will only be a temporary fix if it works at all.

As long as you are right there, test the resistance of the TPS through its entire range.

 

Im sure the TB could use a good cleaning.......but why did this used to happen only when i came to a stop and now it happens all the time. Thats why I suspected the IAC. I will get into the TB today though. Is there any way to test the IAC? Thanks.

 

Couldn't this also be a torque converter clutch problem?

 

dont say that. actually i JUST had a new trans put in (turbo 350) and it was doing this before the tranny swap......