If I kick it into neutral while slowing to a stop,it idles from 900 to 2100,bouncing back and forth.It does it until I come to a complete stop.If I hit the gas to the floor and let up,it will quit doing that before I come to a stop.
FYI,I dont know how old the O2 was and just changed it,it still does it.?????

Does it do it all the time, or just after the truck is warmed up? Is it running hot at all? I assume the CEL hasn't come on, allowing you to pull codes? When the truck is cool, pop the radiator cap and check your coolant level. Usually if the coolant is low, though, it will bounce back and forth like that constantly after the truck is hot.... and won't stop when you rev it up.

Beyond that, cracked/broken/disconnected vacuum lines will mess up your idle. Good luck <img src="/forums/images/graemlins/kewl.gif" alt="" />

Does it do it all the time, or just after the truck is warmed up?


Now that I think about it,only when warm.Hi idle until I stop.

Is it running hot at all?
No

I assume the CEL hasn't come on, allowing you to pull codes?
No

When the truck is cool, pop the radiator cap and check your coolant level. Usually if the coolant is low, though, it will bounce back and forth like that constantly after the truck is hot.... and won't stop when you rev it up.

I will look at that.

Beyond that, cracked/broken/disconnected vacuum lines will mess up your idle.

Thats why I replace them all. <img src="/forums/images/graemlins/smile.gif" alt="" />

I'd be suspicious of a sticking throttle plate. Too much air can cause excessively high idling and a throttle plate that's sticking open will allow to much air to enter.

I just had a throttle problem similar to yours. The spring that pulls the bottom throttle peice back isn't strong enough to pull it all the way. The peice I'm talking about is right below where your throttle cable comes in and hooks to the round plate. It then has a linkage that hooks to the lower plate and it's the one with the spring that's sticking or worn. Spray a little WD-40 on it and work it. Mine would kick down if I hit the throttle pedal quickly and let off. Hope this helps <img src="/forums/images/graemlins/confused.gif" alt="" />
Later,
Nick

If it was sticking,it would not stop when I came to a stop,right?It would stick all the time.It does this until I come to a complete stop. <img src="/forums/images/graemlins/angry.gif" alt="" />

No?????????

Definately a weird problem. Try starting the truck until it's warm.....does it idle high? Get under the hood and play with the throttle a little bit....rev it a few times and see if anything sticks.....that's about as much as i can help without seeing it......Maybe if your close to Orlando/Cocoa, I could listen to it and try to lend a hand.
<img src="/forums/images/graemlins/cheers.gif" alt="" />
Nick

I have a 96 passport aka rodeo with some blazer parts. I just had this problem, but I would stall. Replaced the Idle Air control motor, Didnt work, Throttle position sensor, didnt work, then the Intake Manifold Gasket, worked. I havent had any problems in the past 2 months since. Not saing that it is your problem but something to look at. Pretty common on Isuzus from what I understand