Hey all,

I just signed up to the form today and I have a issue with my 1990 4Runner. My truck idles fine when its cold but when I use the A/C, drive for awhile and then shut off, it has a very rough Idle. Normally it stays around around 500 rpms, but today when I got to work and shut it off, the idle went down to 200 rpms and it sounded like it was about to stall.

Im not a big car guy so if you all know what could be the issue please let me know.

 

I wonder if the ac clutch is not disengaging properly.

The AC pump provides extra drag on teh engine.

To compensate the idle is automatically raised when the AC is operating.

I'm just speculating, but if the AC clutch failed to properly disengage when the ac was shut off you would still have the load but no longer have the idle raised to compensate for it.

 

Even 500rpm is too low. Look up the base idle adjustment and raise it till it smooths out. Also, check for vacuum leaks from cracked vacuum lines.

 

Both gareth and hiluxhack have good points, I agree that it could just be as simple as your idle being miss adjusted. When your truck is cold and or the AC is on, the engine idle is increased to help it run while it warms up or to deal with the extra load of the AC compressor. It could just be as simple as you adjusting your idle screw to increasing your idle. I would let your truck warm up and adjust the idle up from there. I believe the 3vze is supposed to idle around 800rpm when warm with out AC on. Im not sure on the 22re but you sound far off what it probably is if thats whats in your truck.

What did it used to idle at? Did this all suddenly change?