2000 Toyota Tacoma HIGH IDLE!

Hey guys new to the site and need some help, So I just bought a 00' Tacoma v6 3.4 4x4 TRD, was not in the best shape but got it 3k under kbb. So had bad motor mounts, trans mount, no cat(straight pipe), cel was on and a high idle. So got TG solid mounts, built a trans solid mount put in a magnaflow cat and muffler.( Sorry for long backstory wanted to give full picture). OK so on to my problem the high idle is driving me nuts! Ive searched quite a bit and found similar threads on sites, my truck idles 1500 constantly warm or not, I removed tb and cleaned also cleaned iac valve, nothing changed. Cel shows knock sensor bank 1 and 2 possible malfunction, my question is are these two problems completely unrelated or is the knock sensors secondary to my high idle? Is there a test on the tps, or iac ? What should readings be? Maybe someone could tell me how they fixed their similar problem? thanks for any input or ideas!

 

Your issue is a lot more involved than the one I had, but I had a high idle like you (even was around 1500 rpm too) and it was a bad throttle position sensor.

Replaced that and everything went back to normal.

I had no CEL warning either, FWIW

 

Thanks for the reply, yeah I thought the tps mightbe causing the high idle, I can manually get the butterfly to close a little further and idle drops slightly but that doesnt seem to be the main issue, the cel is probably another issue on its own. Madjik What prompted you to change tps? Reading or just a guess? I'd much rather change that than iac, cost wise.

 

My idle was at 1500 rpm even when warm, etc... just like the problem you're having.

I cleaned the MAF, TB and IAC, reset the ECU and it still did the same thing.

So I brought it into my friend's shop not knowing what the hell the issue was. He diagnosed it as a TPS issue and replaced it.

 

Ok cool, was just in the garage and tried the propane leak test and found nothing, but I ended up pulling on the throttle shaft and it must have some play because it idled down, I remember seeing somewhere that you can place a washer before spring to "shim" it. Might try that and see. On a side note what does your guys tacoma's idle at after it reaches running temps and is warm? When I messed with t-shaft I got it to come down to approx. 700rpm's. Sounds better but what is normal?

 

right around 700-750rpms is normal for a warmed Toyota 3.4L V6

 

My idle on my 2000 is usually right around 600rpm.

 

Pretty sure mine is at 750 rpms.

The needle is dead horizontal.

 

Ok thanks a lot guys, think my t-body is a little worn I'm gonna shim my linkage and that seems like it'll work. Next issue will be my knock sensors and I'm gonna do my timing belt while I have the motor apart. Thanks for the replies!

 

had the same problem with mine after i cleaned it. It wouldnt idle down. I went tow rekcers and got a new one. I think i will sea foam it though.

 

When you replace the TPS how do you adjust it ? Mine will idle low at times and then if I disconnect the battery it idles high low high low continuously like someone is hitting the gas and letting off. Any suggestions?

 

the TPS is non-adjustable. It is run by the ECU. What do you mean you disconnect the battery? Do you leave it disconnected for over a half hour? If not , try it. it resets the ECU to learning mode and sets itself by the way you drive for about 50 miles.

 

I'll try that. Thanks. Mine is a 2003 and you can loosen the tps screws and it has probably a quarter inch adjustment.

 

Just a heads up when I did my valve cover gaskets I (not very intelligently) missed the plug for the knock sensors (it's tucked in front of the top of the timing belt cover, which you don't need to remove) so if you have both banks for your knock sensors throwing a CEL it might be worth looking for an open plug the PO might have missed

 

So when i disconnected the battery and reconnected and started the truck , the engine surged from 1000 rmp to 2000 rapidly. It would go high low high low Possibly a TPS?