Ever since I first bought my 4runner it has has a bad idle. When I was going to buy it, a mechanic checked it, took out the throttle body and IACV and told me the IACV was not functional. I bought a used one and installed it, and for about a week and a half it idled perfectly.
Before IACV change it would idle so slow it would die if I diddnt give it gas in the morning, and after driving for a long time it would be almost 2k.
Right after IACV change it worked great, started at about 1100 and settled at around 750.
Now it idlea poorly again, and changes randomly and quickly. It used to just go up the longer I drove but now it just goes up and down from 500 to 1750 randomly. Does anyone have any ideas of what could cause this?

 

Have you checked the specifications on the TPS with a multi-meter?

 

I have not. What specifically do I need to do to check? What would symptoms of a bad TPS be? Ill do some research.

 

With that random RPM jumping, that is one of the symptoms of a TPS out of adjustment.
If you can use a multi-meter that's half the battle.
Read this link.


www.4crawler.com/4x4/CheapTricks/TPS/index.shtml