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Question about a fluctuating idle in a Grand Prix GT-3.8

nickdemio

nickdemio

New member
I have a 2001 Grand Prix GT-3.8 and i have a problem with the idle. When i start my car it idles between 2000 to 3000 rpms and then back down..and sounds like it wants to die out..unless i give it some gas or put it in drive( and idle stays normal) I've put a brand new TPS sensor on, i've cleaned the MAF sensor and dnt kno what else to do or what could be causing this..Plz Help!!!
 


Try cleaning/replacing the IAC. Also, may want to remove the throttle body and clean it out really well. Stuff builds up in there over time and causes wierd idling. Don't forget to replace the TB gasket when reassembling or you will have a leak as there is coolant running through there.

The only other thing that comes to mind would be a vacuum leak. Spray some carb cleaner or brake cleaner around all the vac. spots/lines while it is running and see if you find a place that either makes it stall out or changes the idle in some way. Might have a warped UIM so be sure to spray around where the UIM and LIM meet as much as possible. I know there isn't a lot of room in the back.
 
Ok..that sounds like something that needs to be done since its a 01..thanx! I also read online that if i disconnect the MAF sensor and it stops, thats the problem. So i just went outside & did that and when i started it up..it wasnt idling funny anymore..so i believe me cleaning the MAF sensor didnt work..prolly just need to buy a brand new one. I also read on here that i can drive around without the MAF connected...IS THIS TRUE??? atleast until i can purchase the new one???
 
You can drive it w/ the MAF disconnected, but be very very easy on it as it is now running off of default tables for Air/Fuel, etc. and will not adjust. Don't get on it or go WOT. Just drive gently and you should be ok.

Also wouldn't drive it this way any longer than needed. Check out Rock Auto and see what they get for a MAF. Yours should have a part number on the black top portion of the MAF sensor, something along the lines of AHM-????. Make sure you buy the correct one.
 
If its dieing on u w a new tps and a recently cleaned maf id say go ahead n replace the IAC sensor. Its most likely your problem. That or that thing we always refer to w idle problems; a vacuum leak
 
Ok...will do! Cuz all the places ive called said the MAF sensor will run me between $120-$140 and as far as the IAC..my check engine light is on and i had the code read at auto zone and it came up as the MAF sensor and the EVAP...and the worker at AutoZone said the bad MAF sensor can cause the EVAP code to go off cause the computer is not getting the right info sent to it...
 


By the way...where is the IAC sensor located on a 3.8?? and what is a TB screen..cause i keep hearing about cleaning both or replacing???? Picz would be very helpful..cuz i have very little mechanical knowledge.
 
you dont need to replace either of those items. the screen doesnt go bad unless you break it and the IAT would throw a code if it was bad.
 
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