My 89 V6 (auto) is surging. It's running high revs while in gear (intermittently) and when I switch to neutral they go up past 2000 rpm. I have to apply heavy breaks to keep from rolling in gear.

I can't associate this with hot or cold temps -- sometimes it goes away when the car has been turned off -- sometimes it stays. Sometimes it comes on suddenly and stays, or it never happens at all.

Is it a sensor (I've a vague recollection about an o2 sensor).

I am due for an oil change -- anything I should look at myself or direct my mechanic to look into?

Many thanks

Rob

Clean the IAC:

web page

Frank

My '92 did the exact same thing, off and on for 4 years. The dealership was happy to replace all kinds of things...nothing ever cured it until I replaced the ECU. <img src="/forums/images/graemlins/barf.gif" alt="" /> Hope yours is something minor...although I think I've seen the GenI ECUs much cheaper than my GenII unit was.

Well I cleaned the IAC... we'll see how it goes w/ tomorrow's drive. Many thanks.

Edit to update:
All seems to be running smooth and buttery! Now I need to get that oil changed.

check your ect the ecu use it to control the idle.
Engine coolent temperture sensor.