EXTREME HIGH IDLE

[bslayer]

hello all, my car, a 2001, natural aspirated. My problem. It all started a while back with a code that said the egr valve bad. I forgot the exact code, but bought a used one from Harofreak. Code would never go away and always came back when cleared, but car started and drove good, so I never done anything else.

Fast forward about 2 months later, and wife comes home and said car was running hot. Went out and checked and sure enough, was low on coolant. Filled it up, checked it the next day and was very low again. So I discovered that it was leaking at the pulley side of motor. I thought that I had the dreaded LIM failure. After changing gaskets and figuring out that the gasket failures would only result in coolant in the engine , found the culprit to be the elbows. I had everything back together and it ran great. Even the codes for the egr went away.

Fast forward about 2 weeks. I get in the car and go to town, and the idle just started normal, then it would not come down past 1500 when it was in gear. When I got to where I was going and put in park, it shot up to 3000rpm's. I shut it off, go do my thing, come back and car runs like a top. Over the next few days though, my wife informs me how the idle is doing the same thing every time she drives it now, high idle, 3000rpm,s.

Checked for vacuum leaks, found a cracked hose and replaced and no change. Sprayed the starter fluid all around and no changes. Took car to a vo-tech school that my son goes to and they hooked it up and checked everything. all sensors checked to be good, they also sprayed the starter fluid, checked for codes and such. Everything showed to be as it should. the only thing that showed out of wack, it was showing like a 23% vaccum with the engine off. the Teacher and I decided that it had a gasket leak, either LIM, or UIM.

Fast forward 2 days. I pull intake off and inspect gaskets, found nothing out of ordinary. replace gaskets, get everything back together, start it up, and within a couple of minutes it is running at 3000 rpm's again at idle. I am at a loss and have no idea what to do. throttle body and all have been cleaned, cables are not binding up, butterfly is closing all the way.

I have done a search and came up with nothing. One post had my same problems, but did not have a resolution. I sent the author a pm, but he has not responded. He has been on about every day since I sent pm. Do not know if he even got pm, or just does not want to respond. All help appreciated, I have to get this car fixed within 2 weeks, but I am lost as to what is causing this. sorry for such long post.

[95se]

Throttle position sensor?

[bslayer]

All sensors tested ok. I bought a new one, put it on and there was no change, so took it off and put old one back on.

[95se]

Does it have a electronic throttle body?

[MrT]

Check your throttle cables and connections on the firewall side of the throttle body. The cables should be free of dirt debris, kinks,etc. The cables pull on a circular pulley that is spring operated so that the throttle can return to proper idle when you release the gas pedal. Check for broken springs, dirt,etc.

Start the car and operate the throttle at the engine by hand. You can pull on the cable or turn the pulley by hand. The pull should be easy and smooth and return to the starting position.

Before the day of electronic sensors, throttles got stuck open because of dirt or broken springs. It is worth it to ckeck all this to make sure that it is operating correctly.

Good luck.

[bslayer]

I have un-hooked all throttle cables, and it does not change anything.

[Archon]

Although it will generally set a lean code, try spraying along the corrugated tube from the EGR to the LIM.

[bslayer]

Well, I have tried several different things to no avail, so I will change the gaskets again. The only thing that I can think of that is causing this problem.

[bslayer]

Ended up changing the Idle Air Control valve first, just to rule that out. I was surprised when I started it and the idle returned to normal. I have never experienced or heard of high idle with a bad IAC valve. I did hear some where that it would not throw a code sometimes. Even a high end Snap-On scan tool could not tell it was bad. Thanks to all that gave possibilities.

[vogie01]

Ended up changing the Idle Air Control valve first, just to rule that out. I was surprised when I started it and the idle returned to normal. I have never experienced or heard of high idle with a bad IAC valve. I did hear some where that it would not throw a code sometimes. Even a high end Snap-On scan tool could not tell it was bad. Thanks to all that gave possibilities.

It is not that common of an issue at all. Cleaning the IAC usually works good. Had a high idle a while back and cleaning the throttle body and all sensors did the trick. My clean the old one and see what it does. Might be able to return or sell the part.