Well after conferring w/ a professor of mine, he seems to think that if I had an intake gasket leak, that would cause low vac at idle. I did check the vac at the intake with a new vacuum gauge. I don't have high idle but I still don't have the leak fixed. Also, does everybodys' idle kinda "hang" when their heater is on and a fan going?

Mine will hang whenever the compressor's not running after it's been on teh highway for a while. If the AC or defroster's on, it drops right to where it should be. Other than that, she's got some idle issues too. :P

Vacuum leaks don't always cause high idle. Remember, you've got a computer controlled idle air motor that is trying to seek a certain RPM when you're off the throttle...

I kinda figured that, but would a leak in the intake like that give shitfits to the MAP? I have to go pick up a can of WD-40 to check it running to see if I have a leak. Dino,if you have read any of my other posts, what is your guess on WTF is going on.

I had a leak at the intake manifold on my car and it was causeing all kinds of idle problems. Yes the AIC motor will try and regulate the idle but with a leak that big after the AIC it will cause idle issues and your fuel control will be erratic also.

No probs with idle or fuel delivery as far as I can tell. How about the TB gasket? That's at the IAC.

You can have a vacuum leak in any of the vacuum lines, to/from EVAP, to EGR, to Cruise Control, any vacuum line you have can be a source. Also if a manifold or TB gasket is bad or not tightened down it can cause a leak. You can leak aroun the IAC also. The O-ring on the TPS can be pinched and cause funky idle as well.



15.9 @ 86.7mph

Smooth idle? We don't need no stinking smooth idle.

Mods List:
http://highlander.dsmpower.com/sig.htm

I have a solid idle, that's one of my problems. Did anything that you described cause a good idle/ good drivability problem but loss of vacuum?

I will Paypal IMMEDIATELY the person who can get me pointed in the right direction. (BTW $10 is roughly the cost of a decent 12pk of beer) Also can anybody tell me where the vac line starts for the HVAC vents? This was a problem in a much older car that I have with the line getting hot and cold and breaking. I have nice 800 idle, no smoke, 180 psi in all cylinders, and 10in/hg that has disapeared to vacuum-land.

This is a really really old post, but Erik.. did you ever FOUND the solution or answer to your problem?
Thanks man.
Greatly appreciated.