Could really use some help, very frustrated

[skeptiq]

Seems like one thing after another, and this one has me baffled...

So on the way home from work yesterday, the idle jumped to about 1300 rpm with my foot on the brake stopped at red light. When I let off the gas it was like the car was driving itself. Put car in neutral and it was at 3000 rpm?!?!

Checked TPS and it is at .98 so that's fine. Odd thing is when car is off the throttle stop is touching the idle screw, but when I turn the car on, there is a gap, which is why I checked the TPS thinking it was messed up (this could be normal, I just never noticed this).

I have no idea where to go from here. I want to drive my car off a cliff! Just when it starts running well, something like this happens and I am back to square one.

Any help would be appreciated.

Thanks in advance,
Ben

[Kevin1989]

might be dumb but check and see if the throttle cable is getting hung up somewhere. and be glad its not getting stuck at WOT that happened to me a few times its not fun :lol:

[jack90gt]

might be dumb but check and see if the throttle cable is getting hung up somewhere. and be glad its not getting stuck at WOT that happened to me a few times its not fun :lol:

I have that happen it sucks....:(

[Timido]

Your throttle body spring could be weak and the eng vaccum could be opening the throttle blade.

[03z06vette]

Do the brakes feel the same? I bet its a vacume leak..

[skeptiq]

Brakes feel the same...


Your throttle body spring could be weak and the eng vaccum could be opening the throttle blade.

I think I have a 65mm TB I can put on to see if the spring is the issue, just didn't really want to go down that road... Just googled some stuff and the vacuum line under the plenum may be the culprit, going to check that in a bit...

Bad IAC maybe???

Thanks,
Ben

[Timido]

IAC or vacuum leak would explain ut

[03z06vette]

I was thinking a bad Power brake booster but not now. I would create a vacume leak and see if the idle raises even higher. or check it with a guage. You could also pull the oil fill cap and see if its blowing out or sucking in.

[skeptiq]

Interesting update...

I took off the 70mm TB and put on 65mm I had sitting on a shelf. I cleaned up the 65mm and while I had the IAC off I gave it a good cleaning as well. Put everything back together and fired it up. The idle is now normal. Let it idle for a bit and it is right where it should be so that's good. The only issue is when I rev it will come down to 1100 rpm and sit for a few seconds then drop down to 800 rpm. At least it's not idling at 3200 rpm... Still something up, but at least it's just a hanging idle and not an absurd high idle.

So I am going through the steps to set the idle after long battery disconnect just to make sure everything is set proper.

We'll see. I also bought a new IAC just in case, but haven't put it on.

One question though, what is the function of the allen head screw near the IAC (it was under a rubber cover)?

Thanks,
Ben

[skeptiq]

Got board and made an iac delete plate out of a miller high life can and reset idle and stang is running like a top.

Did some research and several people have done this with great results. Time will tell.

Ben