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07 GT Idle Problems

8K views 16 replies 6 participants last post by  Bullitt95 
#1 · (Edited)
So I've had this 2007 GT 4.6L just under a week and wouldn't you know it, whenever I am coming to a stop and push the clutch in the idle is back and forth. At times it will nearly die on me. I've watched plenty of youtube videos on this but everyone has a different solution. Where should I start to rule out a few things before I start replacing parts? I'm hoping it's as simple as a good clean. Who has had this problem before? What did you do and did it work for you? The car has 66k miles on it and everything else seems to be running just fine. I know I'm not the only one who is or has dealt with this. I appreciate any guidance you may have. Also, there were a few people who said this started after they washed their car and I had just finished a good wash and wax. I don't see how there could've been that much moisture but for those blaming a wash, they claimed going out and running it hard resolved the issue. I'm skeptical to say the least but I'd be glad to go play if that's a possibility.
 
#2 ·
I would start by cleaning the throttle body real good, and clean the MAF sensor in the intake tube, be careful cleaning the MAF, there's info on the forums about it. Does the behavior change with the AC on or off? Do you know if it's running the stock tune or an aftermarket?
 
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#5 ·
your car "looks" pretty stock and that's a good thing. do you know the history of it at all? as said above, a good cleaning of the TB and MAF can/will do wonders. take the TB off and clean it front and back. after you do that. search how to clear the KAM (keep alive memory), then do a relearn of the idle. look the car over as well. do you have any aftermarket parts that you cant see in the pic? I.E. headers, high flow cats, CMDP (charge motion delete plates), underdrive pulleys, stock TB (very important), etc. if the plugs haven't been done before then they will need replaced. I recommend the OEM Motorcraft SP-514 plugs with nickel anti-seize on the snouts, read up on the procedure to change them and don't get to scared. check and make sure you don't have a small vacuum leak altho that would throw a code and CEL. go down to your local parts store and have the codes pulled. the light may not be on but still could be codes. lastly, Welcome to the forum! keep us posted on progress good or bad and hopefully we can get you fixed up. good luck
 
#6 ·
Thank for all the advice, guys. That is pretty much what I had come up with through researching every possibility but to be honest, when some youtuber records himself you don't have a clue whether what he's saying is great advice or the absolute last thing you'd want to do. From what I've seen on AFM so far, the most valuable aspect is you're getting advice from people who have already been through the same situation at one point or another and there are hundreds of people to call someone on bad info. I'm going to start simple and work up from their. Sometimes it may take longer than just buying new parts but I'd like to get cozy with my 4.6 regardless so I think this is a great place to start. Thanks again!
 
#9 ·
Well I took my car to Auto Zone to check the codes and he said it wasn't showing anything. I knew that was a strong possibility but then I said go ahead and test the battery and alternator while I'm here. He said something in the alternator failed. I didn't even get a chance to ask him more about it because he took me inside and quoted me for a refurbished alternator and started helping other people. I find it very hard to believe that my alternator is causing this because of the way the car is acting but maybe I'm wrong. I never even considered that this was the issue so I decided against buying a new one right now. I haven't noticed any issues whatsoever so this was odd. Another point.... What other things should I maybe at least check out or replace while I'm at it? At this point I'm planning to clean the TB, Intake Tube and MAF sensor. The fuel filter will most likely need replacing or close enough to justify doing it so I'm just going to get one. I'm thinking I should probably pull the plugs and check them out. The air filter will only take a second to see if it needs replacing. I'm not familiar with how to reset the KAM or relearn the idle but I'm going to see if I can find something on here about it. Sounds like I'll be having some fun this weekend! If any of you has experience with the KAM process I'd appreciate it.
 
#10 ·
He said something in the alternator failed.
It's possible that one or more diodes has failed, resulting in a small AC current leak that could be playing havoc with the sensors, particularly the cam position sensor.
However I recommend that you follow the advice already given previously and have the alternator diodes tested before you spend the $$$ replacing the whole unit.
 
#11 ·
Some of the things mentioned are so inexpensive, or even free, that they are no-brainers. Fuel filter is cheap and an easy job (there are GOOD YouTubes on this), cleaning the TB and MAF are as good as free, and I would just go ahead and change the plugs, no point doing all the work of pulling them and then putting them back in.

As for the alternator, good advice above, and the alternator is, I believe, a weak point on these cars.

Good luck on this, and keep the thread going.
 
#12 ·
Some of the things mentioned are so inexpensive, or even free, that they are no-brainers. Fuel filter is cheap and an easy job (there are GOOD YouTubes on this), cleaning the TB and MAF are as good as free, and I would just go ahead and change the plugs, no point doing all the work of pulling them and then putting them back in.

As for the alternator, good advice above, and the alternator is, I believe, a weak point on these cars.

Good luck on this, and keep the thread going.
 
#13 ·
Here's an update on the situation. Since I had warranty left on the car I decided to take it in and see what they would do for it and I figured I could sjmply supplement their remedy with the suggestions on the forum. After driving the car they decided to check for any codes which I could've told them would be none. He removed the intake tube and the throttle body was slightly dirty but not nearly as bad as I anticipated. He went ahead and cleaned it out just in case and followed it up by relearning the idle. He drove it again and said it was much better but still pulled it back into the shop. It looked like he adjusted the idle but he said he didn't make the adjustment. He released the car back to me and said it was good to go. Immediately after starting it up, there was a noticeable difference in the idle. When pressing the clutch, even with the A/C on, the idle held at a thousand for a few seconds and then dropped to about 600. It definitely didn't fluctuate and never dropped below 500 so the issue seems to be fixed. My fear is that he just cranked up my idle some and avoided fixing or identifying the real problem. As of now the car is running strong so I'm not complaining but I find it hard to trust mechanics because of past experiences. No offence to the mechanics out there but I'm sure you understand. He said he never tested the diodes in the alternator because there was no reason to which sounded like he just didn't want to have to fix it but I didn't push the issue. What're your thoughts after the updates? Any red flags or suggestions from this point? Should I be happy that my rpms aren't bouncing all over the place or stalling me out? Thanks for all of your help. You guys are a great bunch and I'm glad I found AFM. I'm looking forward to talking with everyone in the future.
 
#14 ·
Others have mentionned very importants steps which are cleaning the throttle body and MAF. If that doesn't work, the Throttle Position Sensor (TPS) is a known weak point on these cars that cause intermitent idle problems. Also, try to disconnect battery for 30 minutes and reconnect it. After you do that, relearn the throttle positioning by pressing on gas pedal while the keys are on ON but the engine is OFF (there are many clear instructions about this out there). You may also check the voltage on your TPS and make sure it's right. If it's wrong, you can try adjusting it or buy a new TPS for about 50$.

PS: I know because i've had this problem. I decided to change the whole throttle body though just because i had a good price, and my idle is back to normal with no fluctuations.

Good luck! it's a problem that took me a long time to find the solution because it can be so many things. Most commonly though it just needs cleaning or a new TPS.
 
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