High Idle, different from surge...

[EricGRIT09]

Okay, so I've been searching for anyone else who has had the same problems that I am having, and I can't find another situation just like this.

I am having a really bad high idle problem, but with absolutely no surge, and it only happens when the car is warm and in warm weather. On a warm day, my car will steadily idle at 1100 RPMs, but then after driving around and the engine bay getting warmer (still on a warm day) it might idle at 1800 RPMs. Drive for another 5 minutes and hit a stop light, it might idle at 2400 RPMs. 2400 RPMs is usually the highest it gets, and if it stays warm it will idle here until the car cools down again. This seems completely random, except for the fact that warmer usually means higher idle.

The car usually idles pretty well (750-900 RPMs) in colder weather probably under 40 degrees. Now that summer is getting here, it is getting much worse

Any ideas? No boost leaks, recirculated bov. I will probably just replace my ISC, all vacuum lines and maybe replace my throttle body gasket.

 

[gonzalaga1]

As a follow up to this post, after months of agony, the culprit here turned out to be the throttle cable being too tight. It was so tight that I had to modify the adjustment bracket by lengthening the holes to allow for even more slack. The fact that I had to do this may point to more problems, but this fix has worked.

Anyone having high idle issues or high revving it hotter weather should definitely try loosening the throttle cable FIRST - it's a 5 minute fix.

Dan

 

[Dsmj89]

It's so funny how we all have these same problems, .
My car is also doing this, just started about 2 days ago. I have no boost leaks and my bov is recirce'd.
My problem is i am driving normal and then when coming to a stop it will either idle at 1000 or drop to 1200 and at times stay at 1400.
It's annoying me and i want to fix it. Tomorrow first thing i will look into re-adjusting the throttle cable as well and inspecting for loose or worn vac lines.
I have also adjusted my biss screw a million times to no avail.
And if it matters or not, when i turn my ac on, the idle used to go up a bit as it should, now it drops, and when i turn the ac off it goes back up... Any ideas ?

 

[Dsmj89]

Sorry to bump the thread so soon but i need a response, come on dsm gurus chime in !

 

[whiteboyz]

i have the same issue, and i tried adjusting the throttle cable but no luck. hmm maybe my dsm dont like me.. but it is very embarising..

 

[johnovision27]

holy crap...... I'll be dammed!!! i had this issue for a long time! always thought it was because of the larger injectors or a crap TB, but loosening the cable actually worked!!!
What are the physics behind that though.... :?

 

[And_44]

Huh, I'm gonna have to check mine now. I took some slack out of my cable a few weeks ago, but today I was working on the beast taking out emission vacuum lines. On the test drive and all day my idle has been at 1200-1300 very annoying. I probally messed with the cable by accedent working behind the engine taking out those hoses. Used to idle nicely at 750-950 depending on engine temp. But any who the idle is so much smoother now without the extra vacuum lines. Hope it is as smooth when I fix the high idle;D