[terribleonexx88]

sometimes wen i start the stang (warm) the idle will fluctuate from 500 to 1300. what could this be?

 

[HMUSN]

tps maybe

 

[Burn'nRubber]

Have you tried cleaning your IAC?

 

[Mike Johnson]

Sounds like the idle air control motor.

 

[91cobra5.0]

i have a simmiler problem, sometimes when i start it up it acts like a missfire and runs really rough but when i rev and hold it for about 10 secs it goes away............. wtf?

 

[kuskye25]

i have a simmiler problem, sometimes when i start it up it acts like a missfire and runs really rough but when i rev and hold it for about 10 secs it goes away............. wtf?

for idle issues id say clean iac and throttle body and check tps voltage, for missing or running rough id say do a tune up...

 

[teal89]

^I'd have to go with tune up first, take your IAC and TPS and clean em with some good grade electrical cleaner spray.

 

[fogged306]

FORDMUSCLE webmagazine: Fixing the 5.0L Surging Idle - Ten Pin Connectors

Check the above link. Also check the sticky about setting your base idle. This is a common problem for these cars and there is a lot of different things that causes it. Start with the stuff thats free.

 

[terribleonexx88]

the iac is fairly new and i have the ten pin jumper harness installed by ford at some point in my cars existance.

 

[u2slow]

mine is doing the same with new IAC, TPS, THROTTLE BODY, TUNE UP, AND TIMING. DEALERSHIP SAID THAT THERE WAS NOTHING WRONG... IT DOES IT RANDOMLY THO