2001 tacoma high idle

The high idle issue has been a problem for me, I just fixed it.

Just for reference I have a 2001 3.4 v6

One day I turned on the truck after just sitting for a few hours. It had a high idle unexpectedly of about 2,000 rpm consistently. Researched forums for a bit and started working on it. I disassembled and cleaned and checked everything. TB, TPS, got a new IAC, cleaned MAF, checked for vacuum leaks, checked air filter, checked drive lines for friction, no CEL, no codes, made sure thermometer was working, etc.


Another forum post pointed me to the TPS (Throttle Position Sensor) and IAC (Idle Air Control valve) as the most likely culprits. I bought a new IAC and installed it, no change whatsoever.


I then unplugged the TPS to check it out and see if I could see any damage, nothing. Plugged it back in and started the car, and boom RPMs went back to normal, 700-750 rpm. Weird?


I revved the truck to test it out, and the revs hung up and took super long to fall back down, and they wouldn't fall back down all the way to the correct idle speed either.


Did some more research and learned that the dashpot on the throttle body might be the issue. I untightened the screw that comes in contact with the hammer of the dashpot from the throttle linkage, therefore disabling it. That fixed the revs and hanging up issue. My RPM is now at a normal 700-750, but my revs drop fast now (because the whole point of the dashpot is to slow that for driveability and emissions).


So the dashpot ended up being broken and keeping the throttle butterfly open an extra millimeter or so, which in turn let more air in and made it idle high. I'm not too worried about the dashpot being disabled, the new dashpot is on the way (part number 22202-62190). it was $95 which is a ton for such a small simple device but whatever. Hopefully this fix will work for you!


Check these forum posts out for some related info:

https://www.tacomaworld.com/threads/updated-part-id-question-dashpot.708549/

https://www.tacomaworld.com/threads/3-4-high-idle-solved.522019/

https://www.tacomaworld.com/threads/part-identification.579429/