96 Mustang GT Idling at 2100 RPM even when warm. (Only happens when car is in park)
So I have a 96 Mustang GT Automatic in my possession currently (that I should note is not mine, it is a family member's who is letting me drive it while they are on vacation) that I have had for about a week now. The car had been having this high idle issue for a little bit and then it went away for a few days. Well yesterday it came back when I went to go run some errands. So the issue is that whenever the car is in park, no matter if the car is warm or cold, the engine RPM rises to 2100 RPM and will not go back down until it is put in drive or reverse. While it is in drive or reverse though, it idles normally when stopped. This is annoying however because when you go to put it in gear the car lurches since its idling so high which can be dangerous as well because the brakes on this car are pretty shit. I tried pulling the IAC Valve plug when the engine was on but that just shut the engine off so I don't think that's the issue or that it has a vacuum leak but I could be wrong. I noticed the coolant level is considerably low though and read that this could possible cause issues with the idle since the computer thinks the car is not getting cooled off properly or something like that. I also read that I should disconnect the battery for an extended period of time and let the KAM reset and relearn where the idle is. I also don't know if its important to add but I think the AC on this car has been deleted because I can't see any sort of compressor in the engine bay where one should be or any AC lines where those should be either. I would like some input though from some actual SN95 owners with the 4.6 though because I have never actually and still technically don't own one of these cars! I am fixing the car while it is in my possession as a favor for allowing me to be able to drive it while said family member is on vacation. Thanks!