the last few days i have driven my car i have noticed the idle surges up to about 2100-2300 rpm and then slowly drops back to normal, i checked for vacumm leaks, checked the throttle cable and the linkage seems to not be sticking at all, is there some sort of sensor that can make the idle surge up like that, or something that causes this problem, car is all stock with 17,000 miles and i have not had a ses light come on... any help would be great..thanks guys

 

Does this only happen when starting your car? That's fairly normal. Happens once in a while with all ours cars.

 

when my cars cold
and i drive out to the stop sign right at the end of my block my car usually idles around there
untill it gets kinda warm

 

when i start it it idles fine when its cold, its when im driving and coming to a stop light and put it neutral to roll up to a traffic light the idle is very slow coming down, takes about 6-7 seconds to drop from 2100-2200 rpm down to about 900 rpm, i have owned 2 other f-bodys and dont seem to remember those having this problem..anyboby know whats going on???? thanks guys

 

Everyone has had this happen happens to me

 

That's happened to me before too. Try cleaning your IAC and throttle body. Sounds like it's sticking or something.

 

i just cleaned the TB not too long ago, ill clean it again tomorrow and do the iat while im at it.. any other ideas will be cool.. i just dont want to bring it to the dealer for something i know i can fix but just cant seem to find it

 

I wonder if everyone who has had this happen did the throttle body coolant bypass cuz that will make it stick from no heat around TB

 

Actually, I read about this while doing tuning. There is a table for when the engine is still cold that raises the idle to keep power to the accessories (power steering, ac, etc.). If you have Tunercat or LT1Edit, you can modify this table to fix it (it seems to happen as the car gets older, my car never used to do it but started after 85K). I have yet to fix it, but this is the solution to the problem that other tuners have come up with. Cleaning the TB and IAC doesn't help, at least it didn't on my car.

 

I had the same problem after cleaning my TB. I took a Qtip and dabbed a little oil where the rod that holds butterfly plates enters the TB. No more sticking after the lube!

 

The programming hasn't changed ... there is a mechanical problem.

Stock programming of the "Idle Speed vs Temp" table only takes the engine up as high as 1050 RPM's. That's at zero deg F.

 

This happen to me before as well. Try tapping the gas a tiny bit when the RPM is still high around 2000. Does it drop back down quickly if you tap on the gas?

What happen to mine was that the TB blades were sticking to the TB. This happens a lot to aftermarket TB where the blades are shifted to one side. If you take out the TB and have light shine through from the back you can see where it is sticking and sand down a thousandths where you need to. I just took out my blades and sand them down a tiny bit at a time until problem is completely gone. I did it three times to completely solve my problem.

cheers

--Hugh

 

you should try pulling the pcm fuse and resetting the pcm, i guarantee it'll stop.

 

thanks for all the replys, i tried a few things but have not road tested it yet cause it was sleeting and some wet snow here the past 2 days.. ill let you know what i find..thanks

 

well i cleaned the tb and the iat and this morning it was idleing way high and was taking about 10 seconds to drop down, i moved the throttle by hand and its snapping back fine and doesnt seem to be binding at all, i just cant figure it out, could it be the TPS SENSOR?? because its doing it at hot and cold engine temps. does the tps sensor have an adjustment like the old gn and t-type cars or is it a straight bolt on shot with no adjustment, im thinking the tps sensor might be faulty... any one agree with me on this one....thanks guys