firestone said my IAC was bad so well ive replaced the Idle AIr Control Valve...reset the computer a few times...cleaned my MAF sensor..got a new pcv valve..cleaned the throttle body and CAI and still the car wants to idle rough and also while driving down the road with the heat on, if i drop it in neu the rpms drop to almost 500 when i hit the brake...(auto trans). I regualrily run sea foam thru the intake...so my ? is wtf is up with it...and its been getiing bad mpg's and sometimes it smells like unburnt gas when i crank up..was going to get a new EGR valve but i have no codes being thrown and i have a code reader... begining to think that this car is going to be the death of me..2003 v6 with 94,000 miles. any help would be appreciated

 

Do the rpms drop down and then pick back up, or does the car try to die. My current and past Mustangs all droped rpms when the a/c condenser would kick on, but the rpms would kick back up in just a second or two. Also, how much time are you giving the computer to reset itself? I've had idle issues with my v6 when I did a windstar swap on it. After a couple of days it worked itself a bit better.

 

30 mins is what ive always heard to wait...then cranmk up let let idle then drive arond for about 20 mins so it will relearn itself..yea it does that with the a/c and heat on but mine does stall or anything..i know that the rpms are goiogn to go up and down witht he heat on but it drops bad enough to when i rev up the engine it almost sounds like im trying ot keep it alive..but no prob while actually driving...but i can feel it "popping" as i call it when im in park just sitting in it..and u can thru the exhaust it is idleing smoothly

 

My cars an auto, and seems like after i changed my alternator out, it likes to dip the rpms down at a stop. SO i throw it into neutral as i come to a stop and it doesnt do it.. Try that and see if it persists.

 

seems like the idle issue has gone but it still sounds like the plugs and wires need changing( and i got the always handy bottle of sea foam!)..soo thats my next plan if i can get a day off when i ts not cold and/or raining