Im having trouble getting my idle to come down. I have it set at 1000 rpms and the most itll come down to is 1500. I know there are not vaccumme leaks...What the real problem is, is when I come to a stop the idle will stay in the 2000 rpm range and take FOREVER to drop...Ive already messed with IAC step tables in LT1 edit although I could maybe drop them a little more...

Is this sound like a mechanical problem or a tuning problem?

 

It's either tuning or your IAC is going maybe. I'm having similar problems with my car after getting my PCM programmed. I told the guy who did it my problem and he said he'd adjust the IAC tables to bring it down. My car idles fine when its stopped, about 1000 RPMs, but when I'm moving and take it out of gear it will jump to 2000-2700 RPMs until I come to a complete stop and it also takes a few seconds to finally come down to 1000 rpms. Also, it sounds like the PCM is trying to kick down the idle on its own but can't if that makes any sense.

 

Yeah it does make sense...I wonder what it is....

 

I had the same problem after I put on my cam/heads and had the ECU reprogrammed. I checked the IAC and it checked out allright so I called up the guy who did my programming. He changed something in his program (not sure what) and it returned to normal. I'd say keep playing with LT-1 Edit

 

Ok...do you have any idea what it was?

 

Not really, but I think it's a little more than adjusting the IAC down. Do you ever go to lt1edit.com ? All sorts of people who know way more than I do talk about this stuff over there. Sorry I can't help further.

 

Did you start with the basics..... backing off the throttle stop screw? Did you check the IAC counts at that point? Then check the TPS. If the TPS voltage isn't under 1.0V, you'll be in the "follower" table... the one that keeps idle elevated when you "coast down". That's the table that keeps high until your car comes to a complete stop.

 

You inadvertently awnsered a "problem" of mine. My idle would stay high until I came to a complete stop. Which, I really didn't care since I wasn't worried about it until I was stopped...lol

I would check the throttle stop and if you have a bigger throttle body, especially a bored stock one, you better check the blade clearance on it, it could be rubbing and not shutting correctly.

-Shannon

 

The throttle stop screw is backed off all the way. I havent been able to check the IAC count.

I do have a low TPS voltage code though which seems to be the root of my problem...I just need someone to expain to me how to test it with my voltmeter since I dont have a scanner handy..

 

So anybody know what to look for in LT1 edit to fix the high idle when you start the car??? I've been having that problem too since blower/programming.