Hey all, I have a 1992 rs v6 manual, and lately its been running pretty odd. First off, when sitting at an idle, my rpms will drop to about 700 rpms, then rev right back up to about 1400 rpms. Once i give the gas a little tap it'll smooth out back to about 1000-1100 rpms. Also there is a weird whistle/whine coming from somewhere in the engine bay. Seems near the alternator or the intake manifold.. thinking maybe intake manifold gasket? Now my biggest concern is when i press the clutch in regardless what gear i am in, it will rev up to about 4000 rpms. I am pretty sure that is not suppose to happen lol... any imput would be greatly appreciated. Thanks

 

Def sounds like a vacuum leak. Fix the leak and see if that fixes all the problems.

 

Exactly what Ftr said.......hook it up to a scanner and get Metric KPA vacuum reading while in park and idle and then if all possible get the reading while driving (this obviously will take two people since you have a manual trans).

 

how do i do that? Kind of a rookie.. but i am trying real hard to learn.

 

Trace your vacuum lines extremely carefully. You'll likely find one unhooked or broken. A vacuum diagram for your motor is probably available on TGO somewhere. No need to test anything just go have a look-see.

Just so you know what's happening, when you push in the clutch it's letting the driveline load off of the engine (neutral) so when the engine sucks in air to idle itself it's finding extra air through the broken vacuum line. This will cause it to rev higher than it should since there's no load on the engine.

 

Another way is if you have a propane torch, start the car and trace the vac lines with the propane torch on but not lit, if the engine revs up you found your leak.