cupieking

So, I just bought my 1991 4Runner and it has been a long awaited dream... I am having a problem with the idle though. When I turn the A/C off the trucks sounds like it is about to stall and much like it has some sort of Cam. When I turn the A/C on and the fan on 2 or 3 setting, it idles fine. Any help would be appreciated.

Junkers88

What does it idle at without the AC on? I ask because it sounds like it might be sitting at too low of an idle.

cupieking

I am not sure of the exact idle speed. It basically lopes and sputters without the AC on. As soon as I turn on the AC it smooths out and runs fine.

Junkers88

Does it have a tach in the dash gauges? If so then this will be easy. If not then we have something else we can try.

cupieking

I do not have a tach in the dash. I did notice another factor today though. It doesn't sputter with the AC off when the engine is cold and not warmed up. Could it be my computer that allows for more gas because of the temperature and then once its warmed it restricts the amount? Timing? Who knows......

Swim

I have almost this same problem. I just bought my 1990 today, I KNOW it needs a headgasket, but when I moved it to my shop today (first time driving it) it started out just fine... once it warmed up it started to idle @ 500rpms, then 1000, then 500, then 1000... once I stepped on the gas, the problem was gone. When I let off the brake without adding gas or in gear, it raised the rpms to 1000, 2000,1000,2000,1000.... again, once I stepped on the gas, it was gone.

Junkers88

Your Idle Air Control Valve is what adjusts the idle when the engine is cold/warm. Next time your around the truck do me a favor and increase the idle a little at a time until it stops sputtering. Then turn the AC on and see if there is a huge change. I really think it is idling too low.

Junkers88

That sounds like a bubble of air in the Idle Air Control Valve.

cupieking

Junkers, I will check out my truck when it quits raining here and as soon as Uncle Sam gives me some time off. I do really appreciate all your help. I will update you when I find the culprit.
Thanks

Tadd

NYChopshop

are you talking 3vze 3.0l v6, or 22re 4-banger? Lets see some pics. Sounds like the idle air controller to me too. Also, check on the health of your vacuum system and pcv valve, but I'm pretty sure I didn't need to mention that.

vsuperman

i have the same problem too.. I found that my idle screw moves when i give it gas. I dont know if this was the right fix but i put some tephon tape around the screw and re-set the idle to 900 rpms. seem to be working. i also advanced the timming just alittle bit.

22re 1995

vsuperman

That sounds like a bubble of air in the Idle Air Control Valve.

where is this located pics help thanks

Swim

Which one of us are you referring to? I've got the 3vze located in Anchorage Alaska

Junkers88

The IACV is located under the throttle body. I'll try to find a picture here in a little while.

TNRabbit

Have you adjusted your hot idle yet? The IACV idles up the engine when the A/C compressor kicks on, so if it's dropping down too low when the A/C isn't on, you need to adjust your idle. The idle screw is FLAT HEAD & is RECESSED into the front (grill side) of the Throttle Body. You can see it when standing directly in front of the truck.