Mustang won't idle
#1
Mustang won't idle
Hey guys - so the past couple months I've been having some problems with my 2002 Mustang GT idling. (I have done a number of searches on here, and tried a couple things I found, with no improvement).
So this all started with it sounding like a French horn while idling - indicative of a failing IAC. So I replaced the IAC with one I bought at O'Reilly's auto parts. After replacing the old faulty one, and clearing my KAM, my car would idle around 1k - not good, but no more French horn under my hood. I went back to O'Reilly's and exchanged it for a new IAC, thinking that the new one may have been a little faulty itself. The second new IAC, however, still idled at 1k - so in an attempt to put a bandaid on the situation (so I could get to work) I put a copper pipe cap in the vacuum line leading to the IAC to restrict the air flow, so the idle would be at the right spot. Note - with the pipe cap, I cant use the A/C or defroster, as the idle would dip to sub 500 because the IAC would not compensate for it. Next, I replaced the TPS and cleaned the MAF in hopes that it would idle correctly - but no improvement was seen with these. I also checked the vacuum lines, and as far as I can tell they're fine.
Now it runs fine with the copper pipe cap bandaid - but I'd still prefer to fix it completely before summer, so I can use the AC. Do you guys have any idea what the problem may be at this point? I would rather avoid taking it to a mechanic, since I have no other way to get to work. Sorry about this being a little wordy, I just wanted to provide all the info I could (my mods are in my sig as well).
Thanks in advance!
So this all started with it sounding like a French horn while idling - indicative of a failing IAC. So I replaced the IAC with one I bought at O'Reilly's auto parts. After replacing the old faulty one, and clearing my KAM, my car would idle around 1k - not good, but no more French horn under my hood. I went back to O'Reilly's and exchanged it for a new IAC, thinking that the new one may have been a little faulty itself. The second new IAC, however, still idled at 1k - so in an attempt to put a bandaid on the situation (so I could get to work) I put a copper pipe cap in the vacuum line leading to the IAC to restrict the air flow, so the idle would be at the right spot. Note - with the pipe cap, I cant use the A/C or defroster, as the idle would dip to sub 500 because the IAC would not compensate for it. Next, I replaced the TPS and cleaned the MAF in hopes that it would idle correctly - but no improvement was seen with these. I also checked the vacuum lines, and as far as I can tell they're fine.
Now it runs fine with the copper pipe cap bandaid - but I'd still prefer to fix it completely before summer, so I can use the AC. Do you guys have any idea what the problem may be at this point? I would rather avoid taking it to a mechanic, since I have no other way to get to work. Sorry about this being a little wordy, I just wanted to provide all the info I could (my mods are in my sig as well).
Thanks in advance!
Last edited by HasABetterSN; 04-03-2013 at 07:23 AM. Reason: edit
#3
So let me get this straight, you capped the vacuum line that controls the IAC and the car idles normal. Correct? Then you have a vacuum leak somewhere between the throttle body & cylinders. Otherwise the car would stall. Its probably the throttle plate not fully closing or an upper/lower intake manifold leak. Good luck...
#4
So let me get this straight, you capped the vacuum line that controls the IAC and the car idles normal. Correct? Then you have a vacuum leak somewhere between the throttle body & cylinders. Otherwise the car would stall. Its probably the throttle plate not fully closing or an upper/lower intake manifold leak. Good luck...
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