smurray

My car has been idling somewhat erradically and high lately. It normally idles at 1100-1200RPM, but its been going as high as 1900 and hanging there until i hit the breaks. Could this be a vacuum leak? The other thing is that i have been hearing this high pitched sound that could either be something grinding internally in the engine or a hissing leak.

The thing is i put 350 miles on the car today and all the vitals looked good, and i didnt get an SES or anything. The car sounds normal and pulls like it always does too. All this makes me think that maby in the colder weather a hose cracked or something...

Any ideas?

Thanks,

SM

the_merv

iTrader: (88)

Sounds like a possible Vacuum Leak, check everything just to be sure.

conan

iTrader: (5)

You can start the car and take a tourch just turn the gas on... DON'T light it and wave it around the intake manifold and TB if the rpm's climb you have a vac leak. Have you done any mods lately?

dman69

Where do I find the intake manifold so that I can check for a vacuum leak?

the_merv

iTrader: (88)

It's bolted to the top of the Engine inbetween the Heads.

jsteele90

iTrader: (13)

seriously??

firehawk#682

iTrader: (19)

If you are serious you shouldn't be working on your car. Just take it somewhere and have them look at it.

blubox

iTrader: (5)

Come on guys don't be like that to him. He can still trace down a vacuum leak without having to pay somebody $100/hr diagnostics time.

They'll charge you $100 man just to tell you were the leak is, then tax you out the *** to change a hose. Try to track down that hissing sound, that's going to be your leak. That's making your car sound like it's cammed, lol. Once you find where it's coming from then try to see if you can replace that hose. If that part is too difficult then take it somewhere to have them replace it but don't get charged for diagnostics...

Trace all the hoses comeing off your Intake manifold. It's the big black composite plastic piece that your fuel rail, fuel injectors sit on top of. If you still cant find it, it's what your throttle cables/brakcet is bolted to. It's likely a hose comeing off there. Feel around the back of the intake manifold as well but be careful because you have a oil pressure sender back there that's easy to break. There is a plastic T coming off the back that is connected to the brake booster. Just be really careful and you should be able to hunt it down. Good luck.

scottHMT

iTrader: (5)

I have this hanging idle problem too, doesnt bother me. Not a vacuum leak either, manifold is sealed up tight, all hoses etc etc, i tried finding it but just ended up chasing my tail

blubox

iTrader: (5)

Do you have a ported TB? If so that could be the problem if RPMs don't come down when you push the pedal.

griftymcgrift

iTrader: (1)

i was playing(cleaning the engine bay) around with my car one day. i disconnected a few wires, then put them back when i was done. when i started the car the idle was very high like 1900 and i drove it to see if it went away. i shut off the car and unplugged the TPS and plugged it back in. when i started the car it idled good. just a thought.

the_merv

iTrader: (88)

^^From what i know and have seen, that it some sort of reset..but from the sound of yours you might have had a bad connection.

Charliet

I am having an erratic problem. On accelleration my LS1 sometimes stumbles , and sometimes has a rough idle, but not always. Do you think a sensor is going bad?

spyterus

iTrader: (13)

I'm having the same issue as the original poster, I recently put a ported TB. What is the problem? How can the erratic idle get fixed?

blubox

iTrader: (5)

Sounds like bad plugs possibly, how old are the plugs, does it straighten out at high RPM?

Your TB blade isn't seating properly, you can try to fix it by loosening the T15 screws on the blade and open/closing it a few times to try to realign. I tried to do it on mine and it fixed the problem a little but not all the way. My TB was bought used from another user though, and not my original. The TB I bought had the idle hole (the hole drilled on the TB blade) drilled out alot more then stock because it was a 480HP h/c car. Mine is stock h/c can so I didn't need all that air flowing through on idle. So I had to put my stock TB back on. If this is your stock TB that you had ported then try to fix it how I described. If it's not your stock TB then check to see if the hole on the TB blade is bored out if alignment doesn't fix the problem completely.

blubox

iTrader: (5)

Oops one thing I forget to ask. Is your car also hissing like the original poster? If so then you probly have a vacuum leak.

smurray

just for clarification im the OP and i do know what an intake manifold is...

I drove the car home today to put it to rest for the winter and the problem was less pronounced. The only reason i posted was because i was thinking maby it could be something other than a vacuum leak... its really cold here and i hate looking for these things... ill probably just leave it in the driveway til spring.

blubox

iTrader: (5)

I hear you SMURRAY, I was aware you didn't ask where the IM was. I'm sorry for getting off topic in your thread. Those responces were to DMAN69. Sorry again for getting off topic.