Random high idle 3.4L taco

[blakes]

I've had this 2000 taco with 3.4L 220k miles for a couple of years now. When I first got it, it had a random high idle that would come and go.

It went away for probably a year and now it's back.

I don't think there are any vacuum leaks and I replaced most of the vacuum hoses a few months ago.

I don't think it's the throttle cable.

TPS? Or ???

 

[Kaptain]

Don't rule out the coolant line that goes to the temp sensor.

I've had 2 (neither a 3.4 though) that had partially blocked lines, preventing the hot coolant from reaching the sensor. This caused an intermittent high idle since the sensor would think the coolant was not at operating temp.

That was a bitch to figure out and a good reason to never use the radiator stop leak shit.

 

[rattlewagon]

check that idle air control valve.

 

[slab]

Just had a frustrating couple days on my own 3.4 with a high idle after sitting a while. Ended up being a stuck IAC valve like was mentioned. You have to pull the throttle body off to get to it, it's the one directly underneath. Once you're there it's a 3-pin connector, bench test it before sticking it back in because I had mine in and out a couple times, just needed to free it up manually to get it to move even after cleaning. 12v to the center pin, connect power to the top or bottom pin to open or close the valve. Hope that helps.

 

[blakes]

Just had a frustrating couple days on my own 3.4 with a high idle after sitting a while. Ended up being a stuck IAC valve like was mentioned. You have to pull the throttle body off to get to it, it's the one directly underneath. Once you're there it's a 3-pin connector, bench test it before sticking it back in because I had mine in and out a couple times, just needed to free it up manually to get it to move even after cleaning. 12v to the center pin, connect power to the top or bottom pin to open or close the valve. Hope that helps.

Ya thanks man, the last couple of days it's ran fine. I need to replace a u joint in the rear driveshaft, then start messing with the IAC.

Is that a big job? Should I get a gasket kit?

 

[slab]

Not a big job. This guy has a great video of the whole job if you want to go into it prepared. I did not replace any gaskets.