I'm having a strange idle problem on my 93 4runner. After running the air then turing off the motor, on restart my idle will be very low and stall out. If I hold my foot on the gas for a few minutes then let off it will be fine. It only does this if i run the air, starts and idles fine if the air hasn't been on.

 

what is you idle with nothing on when the engine is fully warm?? if its below 900 you might want to bring it up to about there (I like more 990)via idle adj screw on the throttle body.

check you air filter too make sure its clean, and if its a k&n that it is not drenched in oil.

 

It idels around 900. Filter is good.

 

When AC comes on, there's suppose to kick a relay to keep the engine RPM idle up.
Check TSM for info. I don't have it handy.

 

There is a VSV on the passenger fender that controls the idle up when AC is turned on. The vacuum hose routing is described here:

forward VSV (gray connector): This controls the idle up for the air conditioning and has a short vacuum hose that goes from the diaphragm to the fender side of the VSV, and a vacuum hose that goes from the engine side of the VSV to the T fitting in hose #2. There are two larger air hoses coming out of this VSV to provide extra air with the A/C on. Hose #2 goes to the black fitting on the plenum, lower right side of the 3 fittings arranged in a triangle.

https://www.yotatech.com/forums/f116.../#post51141054

The FSM procedure on how to test it is attached. Check the condition and tightness of the hoses and if nothing seems wrong, remove it and do the tests. Good luck,
Bugs

 

I havent checked the VSV yet but my truck does this when i run my air no matter if the A/C button is on or not.

 

Aah, when you said "air" I thought you meant air conditioning, but you're talking about the fan motor running I think. With engine running, what happens when you turn on the A/C. If the engine rpm increases slightly, the the VSV is fine. If the rpm decreases and the engine runs rough, then the VSV or vacuum hoses have a problem. I'm at a loss as to why running the fan would cause the idle to be low the next time you start the truck. Other then a very slight drag caused by the increased demand on the alternator, the fan isn't related to the idle speed. Good luck and sorry I can't help more,
Bugs