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jhennessy
10-12-2007, 05:11 PM
when the engine is cold the idle is normal - around 850-900 or so but when the engine becomes warm, say after driving for about 15 minutes under 30 mph the idle becomes 1100 and remains there. this is a recent development and I have not driven the Mustang very much or very hard - may be 10 miles every other day or so...any ideas???
03silversvt
10-12-2007, 05:30 PM
Yeah thats backwards. It should be higher when cold because of the IAC. This is where I would start even though I dont know much about the 02's. If possible reset your base idle where you want the rpms to be. Do this after the engine is warm. Then Clean the IAC real good with brake cleaner.
jhennessy
10-13-2007, 02:30 AM
Yeah thats backwards. It should be higher when cold because of the IAC. This is where I would start even though I dont know much about the 02's. If possible reset your base idle where you want the rpms to be. Do this after the engine is warm. Then Clean the IAC real good with brake cleaner.

yeah, the thing is I replaced the IAC back in either April or May this year...and I do not think it is possible to adjust the idle rpm without a tuner. this just doesn't make any sense.
MichaelsLilGray
10-13-2007, 07:55 AM
Mine is having the oppisite problem ROFLMAO If you replaced it earlier this year.. take it in and have them check it out for you... if its bad it should still be under war.
jhennessy
10-14-2007, 04:19 AM
Mine is having the oppisite problem ROFLMAO If you replaced it earlier this year.. take it in and have them check it out for you... if its bad it should still be under war.

Yeah, that might be a little difficult for me to accomplish as I am stationed in england right now! Nonetheless, I checked all the vacuum lines and noted that the area along the pass. side valve cover is leaking a little oil where the vacuum line enters there...I also checked the IAC and it appeared to be free of carbon
my86gt
10-14-2007, 01:37 PM
you should be still be able to adjust your idle never heard not being able too, if you have a throttle body it should have an idle screw on it.
white35th
10-14-2007, 01:50 PM
The Idle screw in the modulars is a fallback failsafe in case of failure of the idle control valve. The actual idle is controlled by the EEC. Any any leak in the vacum(never could spell that) system after the buterfly will cause a high idle.
jhennessy
10-14-2007, 02:51 PM
the idle seems to be ok now...I don't recall doing anything that would have had an impact but I'm not complaining...
white35th
10-14-2007, 08:14 PM
the idle seems to be ok now...I don't recall doing anything that would have had an impact but I'm not complaining...

If the battery was disconected the Ecc has to relearn the idle parameters and will do what you described.
jhennessy
10-15-2007, 01:47 AM
yeah, that's the one thing I didn't do though...wierd