got my rig all back together, no coolant leaks today, and Ive been testing driving it today. So Ive had this same problem now really for years, but never have really addressed it. So my truck idles fine upon start up, but when I give it gas and then lightly let off the accelerator the accelerator stays partially depressed, or something causes the idle to stay at around 1500 or higher. To make the idle go back down I have to give a quick tap on the gas an then it goes right back down to normal. It happens while driving too,. So Im wondering if it may be my tps or perhaps I need to grease up my throttle cable? or maybe if I dont give a qick tap my throttle plate isnt closing al the way? anybody have these symptoms? is this indicative of the tps being screwed. One thing Ive noticed is that if my tps comes unplugge while the truck is running it will make the idle jump really high, and then when i plug it back in it goes back down. So my tps should be working, but maybe isnt adjusted. Any help is really appreciated.

I had this problem once on my old 91 4runner. The cable was frayed where it went through the firewall, I had to replace it. I didn't know what it was for a long time, but I would do just like you, tap the throttle. Finally one day it frayed so bad that the throttle would stick open however far I had pushed the pedal and I would have to kill the ignition so it didn't rev way up. Then stop and get under the hood and pull the cable back to idle position. That was a fun trip home. That is when I found out it was the cable.

The dashpot may be plugged up, causing the throttle to close too slow:
- http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml#Dashpot

My vote is for the return spring on the backside of the TPS being gummed up. I live on a private dirt/gravel road and every summer I have to pull the TPS and clean all the grime and dust out that gums it up. Sluggish spring will be obvious once you get the TPS off and work it with your hand. (that sounds terrible!! <img src="/forums/images/graemlins/ignore.gif" alt="" />) Go easy with any cleaner you hit it with. I usually give a short spray of electical cleaner or NC brake parts cleaner while holding the TPS springside down. Spray, work it, spray then let dry or blow with compressed air. <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> Anyways, works for me!

~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

I had the same problem with my truck and this fixed it.

My vote also goes towards the dashpot. Mine is having the same symptoms right now and you posted previously that you are having backfiring problems... makes sense...

Im fairly certain mine is the throttle cable, or return spring. When i notice that the rpms wont go back down i can grab the accelerato pedalr with my hand and pull back slighlty and the rpms go back down, so iether its the cable or the return spring on the throttle body is screwed.

To troubleshoot, disconnect the throttle cable from the throttle body linkage and then see if you can isolate the problem to the cable or to the linkage/return spring.

Throttle cable and housing may just need lubed. My 3.0 needs it about every 6 months. Last time I tried graphite (dry) lube in hopes of avoiding having the petroleum based lubricants 'cook off' inside the housing due to engine heat. So far, the graphite works 'OK', but it's not quite as slick as the SPL 100 lube. However, it's been about 5 months since I used the graphite and it's not sticking too badly. I may try the graphite route again this next time, too.

Mike in AR

So I figured it out. Its the throttle butterfly plate thingy. When I push the accelerator it causes the plate to open and when I let off the pedal the butterfly plate isnt closing all the way, which is leaving the throttle open a little. The throttle return spring was filthy but i cleaned it. It still isnt working properly. I tried cleaning the actual butterfly plate but it wasnt really that dirty. It seems like the throttle return spring isnt strong enough to get the throttle plate closed all the way. Ive adjusted my driving so that when Im about to put the truck in neutral I sort of pop the gas pedal and that seems to give the spring enough "springiness" to get the plate closed all the way.Is there any way to increase the tension of te throttle return spring so that it can close the plate without having to pop the pedal?