my girlfriend has a 95 gt and is having major idle issues with it. when she starts the car the car goes to about 2500 rpm and stays there. and when she gets to a curtain speed its hard to slow down. almost like the throttle is stuck or something but its not. we checked the throttle body and all that and its fine. i have no idea what it could be. i drive an eclipse and dont know to much about mustangs. is it a vacuum leak or something? if so what would it be comming from?

 

could be the O2 sensor, vaccum leaks, idle air control valve, throttle position sensor. my car was doing the same thing for a while, though it's not a mustang, the idle issue could be caused by similar faults.

 

i had a similar problem with my 98 GT. one of the hoses on the side of the upper intake (the piece the TB is connected to) was collapsing and causing my car to do that. check and make sure you don't have any bad hoses etc in the intake area.

 

If you have a vacuum leak you will hear it for the most part. If it's the tps or IAC valve you may get a check engine light or not. I would check all vacuum line for any kind of damage or collapsing. Then go to the tps and iac from there.

 

I dont think you get a CEL with a IAC, definately check that, its a common problem. Either that, or the TPS is fudged.

 

Yes you can because it is a sensor and it will be code 415 IAC system at maximum adaptive lower limit and 416 IAC system at upper adaptive limit, 551 iac circuit failure.

 

BTW, that's OBD1 and OBD2 on the 96+ it will be p0505

 

ok thanks were gonna check for any vacuum leaks in the morning and then go from there.

 

Check for vacuum leaks with brake cleaner........easiest method. After checking for leaks, I would see if any codes were present, even though the SES light hasnt been illuminated.

 

how do i check leaks with brake cleaner?