tuffluck

iTrader: (4)

i don't mod my engine and haven't touched the engine in the while, besides checking the oil. i had to take a 200 mile trip today and i noticed a weird problem - my car idles at 1300-1400 rpms. i checked the throttle cable, and nothing is unusual about that. anyway, i went and ate, and the next time i turned the car on, i turned it on and it sat at 800 idle, where it normally does. after i drove around a little, the next time i stopped it was up at 1300-1400 again. what's going on???

i have an m6; please help me so i can attempt to fix this before i go back home.

yak

iTrader: (15)

Was it cold out, sometimes my car idles high wen its real cold out, then drops down. Could your throttle cable be getting stuck on something?

tuffluck

iTrader: (4)

no, it wasn't cold. i'll check the stuck throttle cable. thanks for the response; any other opinions?

ttyson

vacuum leak?

tuffluck

iTrader: (4)

how would i check for something like that, and what would have caused it?

also, is it bad to drive that 2 hour trip if i have a vacuum leak?

99FormulaM6

iTrader: (21)

it only happened right after you got off the highway?

elderon

Although I doubt it would cause the car to idle so high. Was your AC or defroster on. That will make the car increase its idle slightly I believe.

Zymosis

iTrader: (7)

My first throught was throttle cable getting stuck somewhere. As far as ac or defroster, it does it slightly like you said, but no where near 1300+ rpm.

For a cold start, my idle is 1100 at the most.

tuffluck

iTrader: (4)

well, it would sit at 1400, and then it would work it's way down to around 1100, but nowhere lower. today i got in the car and drove it around - 800 the whole time. then a minute ago i went and ate some food and it was back up near 900-1000 after driving it a while. the engine is also taking a minute to turn off completely after removing the key, which is something it never did before.

in fact, i recently used a can of seafoam in my gas tank because i was told it was a good injector cleaner; i was also told it stopped the car from turning off after the key was removed because you were clearing up carbon deposits in the fuel system. anyway, it's very ironic that only after i used the seafoam did i develop this problem, when that stuff was supposed to cure it!

do you think the seafoam could have had anything to do with the high idle? even at 1000 rpms, although it's better than 1400, it still doesn't seem right. and the fact that it fluctuated from 1400 to 1100, this morning at 800, and then this afternoon at 900-1000 really bothers me. i checked the TB and the air filter and nothing unusual is going on there either.

the seafoam was in the gas tank about 2-3 tanks ago, so i would have thought i'd see the problem if that had caused any by now. another alternative is possibly bad gas? could that cause problems i'm experiencing?

i also scraped my cutout pretty bad yesterday, maybe a sensor got knocked loose when the tip of the cutout scraped (i doubt it, but you never know...)?

CATCH ME

iTrader: (1)

if your car has the ls1 intake manifold on it i would check the egr tube that goes into the manifold...mine did the same thing when i did the free mod to it. the o-ring has to be seated perfectly to not get a leak. otherwise it will hiss and have an increased throttle position. so i t could be that but im not sure. just a thought

tuffluck

iTrader: (4)

well the only mods i've ever done was the tb bypass, a lid, and a cutout. other than that, never touched anything around that area. if it's that o-ring then that would be odd considering. but i'll look at it and see if i can tell anything obvious. thank you.

glennhl

I had a similar problem. Turned out to be a dirty IAC valve in the throttle body. I took it out and cleaned it with carb cleaner and it fixed the erratic high idle.