I've really got no idea why it does this, but my car will idle fine right around 1000 RPM (would probably idle lower, but that's where it's set), but once I drive it around it wants to idle around 2200 RPM or so (and even when sitting in 5th gear at 45 or so, it wants to accelerate when OFF the throttle).

I can then turn the car off and start it right back up, and it idles around 1000 RPM again, then if I drive for even one stoplight, it idles back at 2200 RPM again.

I'm really pretty sure there's no vacuum leaks, I can't find any. And it seems REALLY strange that it idles low when started but high later.

By the way, it's a Haltech E6K. The stock idle control valve (on the UIM?) isn't there. I don't know that there is anything at all that electronically controls the idle on this car. Any ideas?

 

Ok, I found a few vacuum leaks that the previous owner "knew for sure" weren't there. But it still idles high.

PLUS, I just found out this little tidbit:
If I'm driving around and come up to a stoplight and just put the clutch in and hit the brake (or hit the brake then put the clutch in when I'm almost stopped, whichever...) it'll idle high at 2000ish.
BUT...
If I'm driving around and coming up to a stop, if I put the clutch in and mash the gas to rev the engine, it'll rev up and then come down and idle at 1500 or so (still a *little* high, but much better than 2000).

THAT seems really weird.

It'll also do the same thing if I shut it down and start it back up, it'll idle at around 1500 or so when I do that.

 

Throttle body is sticking or throttle cable is...
FC's are notorious for sticky throttle cables if they are original from the factory.

The Haltech'd FC's tend to idle at 800, 1000, or 1200 in my book once the BAC valve is removed.
I dunno why it does this... :P
Your 2200 is a bit higher than this, so this is something else that's causing the problem.


-Ted

 

That might be. I noticed a receipt for a new throttle cable when I bought the car, so maybe the throttle body, I dunno. Never thought to check that.

 

Is this a turbo or non turbo??? Sounds like a vacuum leak but if you are certain it isn't then it must be the throttle cable or throttle body as Ted stated, more likely the cable. First thing is to take a visual, are there any kinks or cracks in the throttle cable housing. If yes replace cable if no disconnect cable from throttle body and push the cable in and out, cable should be free moving if no replace cable if the if yes reconnect cable. Cable adjustment the cable should have a small amount of play when the throttle is closed if no adjust cable until there is some play if yes do you have cruise control? If yes perform similar checks on it. If no then purchase a factory workshop manual and perform all the test associated to the throttle body/emissions. Ok back to the air leak, If it is turbo you may have a crack in the plastic pipe between the AFM and the turbo. Or maybe the check valve inline on the brake booster vacuum line is bad. And always overlooked is a possible vacuum leak at the injectors between the injector and the engine/manifold (always replace these o-rings when R&R of the injectors is performed) best of luck... just some thoughts
-g