HIgh rev idle and bucking at high revs

[UnWanTeD]

I have a 91 s10 2.5L, when i start it up it revs really high and up and down, when i put it in gear the revs go down, but when i get the revs back up it starts bucking until i shift up and the revs go back down, it does this through all the gears, lower gears and worse. It did this once before when it got cold out and stopped after a day or two, then reciently it started up again and has been doing this for 3 or 4 days now.

I have been reading some of the other subjects on here and they sound the same, but i cant tell for sure. I have new plugs, wires, rotor, exhaust manifold, air filter, pvc valve. I dont know what it is, running rich? vaccuum problem? please help.

[BlazerLT]

remove and clean your IAC valve.

Rest your computer by pulling the negative battery cable after for 5 minutes.

Reattach and then start the engine, it will start a little rough but it will relearn its idle. Idle it in park for 2 minutes and then idle it with it in gear for two minutes standing still with the brakes on.

Should fix it.

[xtremetrk]

It should be idling around 900-1000rpm.

[BlazerLT]

Originally Posted by xtremetrk

It should be idling around 900-1000rpm.

Don't post if you don't know.

This isn't a bullshit forum.