Idle Woes--HELP!!

[ToyotaMax]

Hey guys. I've been having some trouble w/ the idle on my  85 22RE. Heres what's up: sometimes, not always, the idle on my truck will "bounce" up and down from about 800 RPM to 1200 RPM. Usually after I've been driving it for a few minutes. When it idles smooth, it's at around 1200-1500 RPM (high). Here's what's weird: when the idle is "bouncing", I shift into 4WD hi/low and she idles smooth at about 1200. When I take her out of 4WD it's up and down again. I just has a new TPS installed, so I don't think that's the problem. Any ideas??? Thanks Guys.

[yotaboy79]

it could be the throtal positioning sensor, my brother replaced his and had the springs in the wrong place and it made the engin lope realy bad and it had no throttle responce, check to make shure that it was put in right, i hope that helps

[84runner]

Theres another post about the same kind of problem that has a few good suggestions you might want to look there