96Tacoma Fast Idle and More

My 96 Tacoma 2.4 is idle and running too fast. It behaves this way shortly after cold start and continues for a few minutes, and then runs fine. Occasionally it will also do a chug or two.
Several months ago, I replaced the fuel pump and fuel filter, and the truck ran fine for about 2-3 months before the behavior started again. I replaced the fuel filter and it ran well for 3weeks. Now the behavior started again. When behaving badly, it sometimes cranks a long time before it starts. Ideas?

 

Is it just when cold outside? and is it about 1500-2000 rpms?

 

It does not seem to be related to temperature. The last major incident was in August. It is occuring now with day/night temperatures 50/35. It ran OK during the cold snap in January.

I did not note the rpms, but your estimate seems about right.

To review- the behavior occurs before the engine gets fairly warm. It does not kick into unusually high rpms until it has run for 2-3 minutes. Then it will be high rpms for 2-4 minutes before it idles down.

 

Okay bad news, nobody exactly knows why this happens and i cant figure it out either.
Try unpluging o2s one at a time to try to single out a problem. Or look at your throttle body for in/out shaft play. maf also is suspect.
Good luck man.

 

I gave up trying to fix it in my truck as i am going to a tdi soon enough.

 

Recent behavior- I turned the Tacoma off while it was still fast idling. It would not restart, just cranked. I will try some of the suggestions.

 

No check engine light???

 

No Check Engine light has been on anytime in the past 6 mo.
Tried starting this morning. Popped right off. Again after a couple minutes, the fast idle kicked in for 3-5 min. Then everything OK. After driving 20 min, I turned it off and then it started right up. Will try throttle and MAF cleaning.

 

Update. Last weekend, the Cooling System Temperature Sensor was replaced. Couple of glitches on first start up. So far, running well.

 

Awesome!!!!!!

I had a code for CTS
Look what mine looked like b4 replacing

 

96 Tacoma still running well.

My CST Sensor looked a lot like Control Cars.