Vacuum Leak I think

First off I did a search for vacum leak and vacum line, and didnt find my problem. I have a original LS motor, I recently did a clutch job, I start her up and the RPM is high like 2300 rpm, when she settles after getting warm she falls down to like 700 (normal) and jumps back up to 1500, then falls and jumps between 1300 and 1500. To me it all points a vacuum leak. But I want help on where I should look first to diagnose my problem. Or how do I diagnose my problem. Could it be the EGR valve gone bad??



so is your idle hunting?

I dont understand the word hunting?

you can check and clean ur IACV ( idle air control valve) ? there could be a lot of this making it idle weird like that.

I dont understand the word hunting?

Is the speed of the motor going up down like it is hunting for the right speed (RPM)

kinda sounds like a fast idle thermo valve issue. I have heard of problems caused by the FITV that sound like what your having. Try bleeding all the air out of your cooling system. It’s just an Idea…hth

It is hunging for an idle. I will check those things today. Thanks guys

here is the link to the teg tip about the FITV -

Just for an update. I pulled off the FITV and turned it back in, it helped a little but I still had problem. It turns out there was a hose loose that goes into the back of my intake manifold. Thanks for the help all.