I have an 88 4Runner, 3.0, 5 spd that is having a problem that has me stumped. It has been hard to start when it's cold for awhile, and I figured either the cold start timing switch or injector was going bad, but I kept putting off fixing it. Then, about a week ago, it would start, but not go into a higher warm up idle like it usually did, and it was idling low(about 500rpm). It ran fine once warm. I figured it was time to do something about it. So I took off the TB, cleaned it up(with TPS off),and ajusted TPS to spec. I have replaced the timing switch, injector, and temp sensor and now it's even harder to start and it bogs down until warm. I'm also getting a CEL that shows code 22 (temp sensor). Again, it runs fine once warm and Idles right at 800rpm, but it still doesn't kick into a high idle. Plugs, cap and rotor are new, wires a few years old. I'm wondering if I damaged the wiring on the temp sensor or timing switch when removing them. Any help would be appreciated, I'm out of ideas.

 

My 3vze was hard to start and stumbled and idled fine when it warmed up and the headgasket was bad.

 

A shot in the dark, did you thoroughly clear the vacuum input pipes/tubes in the TB? If you didn't flush them out real good, there could maybe be some junk in one of them. The proper vac level would be insuff. in that hose, etc. Another thought I'm having is since you did do such a precise job cleaning the TB, your idle may need readjusted, and your timing checked, if that don't help. Or, the throttle plate limiter.

 

Maybe replace plugs, O2 sensor?
Try disconnecting battery for 1/2 hr and see if that resets code.

 

This is just a theory:
Your temp sensor is bad or disconnected (bad wire). Your ECU is not able to "know" your coolant is cold and therefore not able to kick in the fast idle mode.

CT

 

There is an idle up path in the TB, Its the big hole on the bottom when your looking into it, This can get plugged or can be malfuntioning, It opens when the warm water enters the TB, There is an access plate on the side or bottom of the TB.

 

Thanks for the replies. I cleaned the TB pretty thoroughly and blew out all passages with compressed air. I suspected the idle air valve that's in the bottom of the TB, but you can't replace it except by buying a new throttle body. If it is the headgasket wouldn't I see some other symptoms like overheating, losing coolant, coolant in oil, or white smoke out tailpipe? I replaced plugs, but not O2 sensor. Anyone know how I can check the temperature sensor circuit? I've replaced the sensor, but the wiring could be suspect.

 

did you get to fix it? What was the problem?