Tberg725

my cars idle suges randomly,it dont matter if the car iswarm or cold it will slowly rise to 2,000 rpms then when i put it in gear somtimes it will go back down to around 800-1000rpms now ive tryedcleaning the IAC and resetting the cars computer but neitherthings have worked im thinking it could possibly be my o2's? but i dont know for sure and my check engine light is onand my car has been running excessively rich any help u guys have to offer is much appreacheated

kilby94

Run the codes and see why your check engine light is on. Do a search and get instructions on a KOEO test. On board diagnostics are always a good start. On my car when it was smelling like fuel sure enough i got the code 91 running lean, and replaced o2's and light wen't off and car ran better.

Texas5.0

I have been having idle problems for 6 months now and I think I just got it fixed last night. Over the last 6 months I cleaned the IAC, mass air, throttle body, replaced all the vacuum lines, put on an adjustable fuel pressure regulator, and the thing that I think finally fixed it was resetting the base idle.

90_Mustang_GT

I have the same problem only my car will idle at about 1100 rpm's. When its cold it wont but as soon as it warms up it stays at bout 1100. No matter if im stopped or not and if im off the gas in town it will go right up to 30 mph and stay. Ive changed the IAC and thats it, what do the stangs normaly idle at? Sorry for stealing the thread.

Texas5.0

I was told to set the base idle to around 850 or so. That setting would not work for my car. If the A/C was on the car died... often... every stop. I set my base idle at 1000 and last night was the first time in 6 months that I drove my car around and it did not die.

mjr46

when you rest the idle there is a strict procedure you must follow...it's on the stickys here I believe...........anyway to make a long story short you reset computer follow base settings get that set shut of reset computer plug IAC back in and allow it to relearn for a few minutes...shut back off then restart this timw with all load accessories on like lights, a/c, radio ect ect....... allow it to relean the idle now as a function of all loads being applied......both parts are critical to follow to properly having a stable idle....if you modded the car then performance mods affect this too expecially on 94-95 mustangs when the cam is changed to a more radical cam.....anyway follow the directions in the stickys and it should work for ya'

Texas5.0

The one thing that I found different on the sticky's around here for the base idle reset was to also disconnect the spout plug. None of the sticky's I found here talked about it, unlessI missed it repeatedly. I tried setting the idle twice with it connected and it did not appear to help. I followed the same exact procedures as I had the first two times but this time I also pulled that spout plug out. Set the idle, turned off the car and then reconnected everything. Then it made a difference. Car is idling better than it ever has. It has not died in two days and thats with the A/C running full blast... it's 92 today with a heat index of 100.

91lxstang

thats about where my idle is but i never have a/c on cause it doesnt work