[8notch8]

Okay, heres the scenario...I bought my 2.3 stang a few months ago, when I got it, it didnt run. I replaced the timing belt,tensioner, cap, rotor, wires, plugs...then it ran like a champ. I was averaging around 24-25 mpg, looking for more power/economy I came here to MM, I read alot/learned alot and started doing mods (cold air intake with 5.0 cone K&N, EGR block off, unplug knock sensor, and set the timing up to 38 deg. total) worked awesome...averaging around 27-28 mpg now (slowing down on the highway helped alot!) But recently I started getting the dreaded "rolling idle" so the first thing I did was clean the shit out of my IAC valve *AND* the passages through the throttle body...still there. So, I switched the 2.3 IAC for a known good IAC from a 5.0...still there. Now the damn thing will die if i let it idle more than about 5 seconds, but as soon as I put the car in drive *POOF* its gone, it will idle fine all day long, until I shut the car off-even if only to start it right back up, then the rolling idle comes back...WTF!
I read the 5.0 posts and they say check the "salt and pepper" connectors near the intake...I looked, not there, what else could this be? Any suggestions would be appreciated...Thanks!

[8notch8]

oh yeah, it has a newer fuel filter, clean air filter, and I did the "carb cleaner" vacuum leak test...no leaks I could find. And I always get gas at the same station that I have been for years in other vehicles with no problems.

[akatagyourit]

Well if you've checked everything, possibility of a wiring going bad. I had the same problem for the longest while and then we came to the determination aka accidently bumping the connector for the IAC whenever I get on the motor hard it will shift out just enough to lose connection. Check that when you get a chance other than that. Pull the codes. Code pulling is one of the number one things to do. Good luck with it. The N/A motors are great for gas milage thats for sure. Just lack in power :-)

[TurboLX]

could be your IAC wiring or try adjusting the nut on the throttle body for idle air

[8notch8]

well, shortly after posting this, I went out and looked some more, checked wiring, vacuum lines...then I think I found it! my o2 sensor was loose, so I pulled it out, cleaned the threads and applied some anti seaze and retightened...I let the car run for about five minutes (is that long enough to go off closed loop?) shut it off, restarted...it seemed better. Tommorrow I will get some drive time and let the ecu catch up. I will keep you posted if that was the source. Thanks

[8notch8]

just an update, the o2 sensor being loose wasnt the prob. cuz it STILL does it. I went through and unplugged every connector under the hood and applied some dielectric grease to all connections...just dont know what else it could be (other than frustrating) anybody else have suggestions?

[TurboLX]

ecu could be done

if its a 5 speed ill sell you the one from my car when it was n/a

[MSO]

disconnect the battery for 20 minutes and try it again