HOLLYWOOD99

My 2000 gt will not in my opinion idle correctly, when i get off the gas the idle hangs around 1500 rpm then after about 15 to 30 seconds drops down to 1000 rpm then down to where i think it should be wich is like 750 to 800 rpm.

i dont know whats up, i cleaned the IAC, or should i replace it?

-Matt

tcuallstar

is this while you are coasting or just sitting there? mine will hang above 1000 while im coasting, and when im sitting there it hangs on the way down at 1500 for a few seconds, and then 1000 then below that. i think it does that to allow for shifts , not sure. if its hanging for a long time it could definately be something else. sometimes its a vacum leak, sometimes its something else. just troubleshoot and you should be able to figure it out

HOLLYWOOD99

no, it does it when im coasting, and just sitting there..

03nittostang

I'd start out by checking for a vacuum leak. might need a throttle body cleaning or could be a idle air control valve problem..sometimes they can short out and not work properly, They cant close all the way and let to much air bypass the throttle plate. Take a can of cheap brake parts cleaner and spray around the intake plenum throttle body and any thing past the M.A.F sensor. but be careful that stuff is flamable so dont directly spray it on the exhaust or plug wire boots. IF it has a leak you should hear a change in engine speed or hear a stumble when you spray the leaking area. If you have a scan tool that will show you live engine data you can check your Fuel trim data. and look for it to increase or decrease as you are spraying around.