Ndrivers

1990 firebird Gta 75k miles 5.0tpi not driven in a long time like 3 years. i did a lot of work but But car starts now every time now.
BUT idle is very high like 2500/3000
I got a new iac and it idles little less. Went from the 3 to about 2500.
I did a vacuum test as good as I could with my limited skills. Couldn't find any.
i did the thing where I undid the iac and turned the key, it moved and fully extended. i belive the video i watched said that was proper procedure for that.
and the idle doesn't changed after warmed up I left it on a for as long as I thought safe like 10 minutes, no change,
also the gas peddle seems to react very slow, i know its already idleing very high but it tkaes a long togo back down to the 2500/300
Maybe the new iac valve is fauly and get a new one?
thaks everyone! and sorry this is ny irst time trying to post and it doesnt seems like they arent getting poested but whatever thanks!

Vader

Welcome Aboard.

After the IAC is fully extended, the IAC electrical connector is then unplugged. At that point, the throttle minimum air position can be set to spec - about 550-600 RPM on a hot engine.

RKeats

Does the idle ever fluctuate or does it stay as if you're holding the throttle? Have you checked your timing? It still kind of sounds vacuum related to me. I had a similar issue with my GTA. When I went to neutral to stop, the idle would speed up as if I were holding the gas. Replaced all of the intake gaskets and adjusted the timing slightly and it fixed it right up.

Vader

There are IAC adder steps for park and neutral, so that might explain a little of what you experienced.

This is the proven method for setting the throttle plate stop screw, even in the SD applications:

https://www.thirdgen.org/forums/tpi/...ml#post6146584

Ndrivers

i got the idle set properly. Thanks!