i got on it the other day and let off and the car stayed at 4500 rpms....
i pulled over and moved the tb cable down so it would go down.
it was only stuck just a little.
i then noticed i forgot to put the oil cap on the valve cover from my oil change..
i plugged it back up and the car did a little better
only sticking at 2200
i drove it a while and it has seemed to fix its self

only mod i have done recently was descreened my maf and ported the **** out of it...
any ideas ?


its done stuff like this in the past
car will idel high from start
i just turn the car off and restart it and it usually gone
this recent time had me worried

 

There are 2 things that can cause your problem.

1) the throttle blades are not closing all the way when your foot is off the gas.

2) there is a vacuum leak


First check the throttle blades. Disconnect the cruise control cable and the TV cable (if your car has one) and test. One of the cables could be holding it open. With the engine off, make sure the throttle blades move smoothly and close completely. You may want to remove the ducting on the TB so you can visually verify it is closing all the way.

If the throttle blades are not the problem, you have a vacuum leak. With the engine running, Get a can of starting fluid and spray it lightly on any hoses, and the TBgasket listening carefully for the RPMs to go up. When they do, you've found the leak.

The PVC hose is common to get brittle and crack, causing a leak. I replaced mine recently because it was shot.

 

could the oil cap being off cause that
isn't that a vacum leak?

 

nah thats not a vaccuum leak. on old school cars there was a breather on the valve covers that essentially did what you did by leaving the oil fill cap off. basicly some compression can get past the rings in your engine and pressurize the crankcase and they used breathers in the old days to let it out the lt1 uses a different system but it works about the same. sounds to me like you've got a sticky throttle cable, maybe try taking it loose from the tb and work the blades of the tb open a couple of times to see if they're whats sticky or if its the cable.

 

maybe that was the problem i took some zep 45 and had some1 pump the gas pedal while i sprayed the cable with it