04 Aztek engine revving, RPM's SOAR!

[jlcjohnson]

Often when we start the car the RPM's go way high, sometimes up past 4000. Sometimes, if we turn off the car and then restart it, it then resets and is fine. Sometimes if we are in a parking lot, after shifting from park to reverse to drive causes the RPM's to surge also. When this is happening the car practically drives itself and we have to ride the brake until we can pull off and turn it off. We have had it checked out twice and had the sensor replaced twice. Any ideas? If we can't get it fixed, we can't keep driving it. Not safe!

 

[melsg5]

Is the check engine light on? Which sensor was replaced, the throttle position sensor? How long after replacing the first "sensor" did the problem reappear?

 

[jlcjohnson]

The check engine light has never come on. I was wrong by naming the replaced part as a sensor. It was instead the idle air control. We had it replaced in Spring and the problem started again this Fall. Any ideas?