high idle....

[evomind]

sometimes my 02 gts exhibits a high idle condition even after the car is warm and has been driven.
ill be driving in 3rd or 4th gear and ill let my foot off the gas and its almost like its in cruise control.
or ill come to a stop and the car will hang at 3k for a couple of seconds, drop to 1500 rpms, then finally itll drop to abt 750 or whatever.
if ya go to rev it, it revs, hangs up there, and does as already described.
usually itll idle and decel normally after abt 15 mins of driving, but the other night it did that for my whole cruise. i finally shut it off and started it up again and it was better but not "right.?
if i had to guess id say tps sensor, but im not sure.
any ideas??

 

[JonB]

Idle Speed Motor
Throttle Position Sensor
Vacuum leak (but intermittent?)

There is a PCV fault that can also cause this.....adding a restrictor in the line 'fixes' it

 

[cfiiman]

Ive posted this before, I had a "hang" issue with a high idle at 1500 for the longest time. Checked a bunch of stuff including the IAC (cleaned it etc.). One day in an Advanced Auto a bottle of techron was on sale for 50% off so I bought one after the reviews on this site and Tom Fluid Guy's posts about it. Within 50 miles my idle was much more normal. Now if it ever hangs I know it is time to run a bottle, may be a cheap, easy fix and it never hurts to run a bottle of techron anyway.

 

[evomind]

Idle Speed Motor
Throttle Position Sensor
Vacuum leak (but intermittent?)

There is a PCV fault that can also cause this.....adding a restrictor in the line 'fixes' it

how do i narrow down the culprit?
is there anywhere i can find a diagram to find where these sensors are?
thanks

btw, jon have you found those header heat shields yet?
thanks

 

[Dan Cragin]

This can be caused by numerous things, too many to list here. Feel free to call me about this and I will walk you through the diagnostics.

 

[dascorcha21]

was there ever any solution to this? i am having exactly the same issue. push clutch in and sometimes rpm flashes to 3k and stays there until at a complete stop for a few seconds, and or as soon as i hit 1500rpm in decel the car feels like it goes into cruise control.. any help or advice would be much appreciated!

 

[evomind]

yes....clean the IAC carefully and see what happens.