I bought a 2010 GT Mustang with only 24k miles. I only owned a couple of weeks and the car started running really bad. I was getting 15-16 mpg on the highway. I took it back to the dealer and they would not touch because it had a Bama tune on it. They took it over to speed shop and the told me and the dealer the only mods the car is the Bama tune, cat back exhaust and a 3.73 gears in the rear.

All they did was re-flashed the computer back to oem. The car still ran rough at idle. However, the car is running way better on the highway. The MPG shot up to 22MPG. Since there was no internal mods like a cam on the motor. The Speed shop sent it back to the dealer. It is there now and the Shop foreman is looking at it.

Anyone have any guesses why it would be running so rough without a engine light code? It is idling very rough and with a low RPM. When you come to a stop, it acts like it is about to stall. It even did stall on me a couple of times.

 

You had a 'tune' and let the dealer return it back to stock?

 

If that is the case, the handheld unit is now locked and worthless, correct? At least until it is unlocked - which may cost.

 

I think so

 

I do not have the Bama tuner. It did not come with the car. They put the car back to oem but it is still running bad. Maybe there is something after market in the engine we do not know about.

The shop foreman can not figure it out. They are sending the car to a local shop that only works on Mustangs plus they do tunes. I hope they are able to sort the car out.

 

WHOA
I thought it was a 4:10 car with cams ?
What did I miss?
How did you come to buy a tuned car without a tuner?

 

So which is it? Cammed up or not? X-Pipe or not?

If the car has aftermarket performance cams, it requires a custom tune and generally gets less mpg. Depending on the cams and the quality of the tune, it may or may not idle smooth.

If stock aside from the the axle-backs, try cleaning the MAF sensor.

I feel like there is more to this story...

 

I thought the car had cams when I bought it. However, after owing it a week it started stall and throw mis-fire codes. The dealer would not touch it since it had a the tune so they sent it over to a local speed shop. I am not sure which one. They took a look at it and called Bama. They said it has no cams according to Bama or internal engine mods. SO the shop flashed PCM in the car back to oem. The misfire codes went away but the car still idles real rough. So the speed shop sent it back to the dealer. The dealer is still unable to get the car to run right so now they are sending it a local shop that only works on Mustang and does tunes.

The car does have a x-pipe and the Bama tune is gone now. The car is back to oem as far as the tune is concerned.

Either the car does have cams and the oem flash is not working with it or it does not have cams and there is something else wrong. I have no idea at this point and neither does the dealer. Bama said when the tune was done on that car by the previous owner the car did not have any internal motor mods. So what do I do form here?

 

Try cleaning the throttlebody, maybe the MAF sensors as well since your at it, then reset the ecu.

 

Good luck! Wouldn't be surprised if the tune was the issue... good move to get rid of that, particularly that brand of tune. That's the danger of buying a used vehicle if you don't know the owner...especially with a tune. You don't know what damage that's done internally already, if tune was bad, etc. And it only has 20k miles? eeek... Only way I buy used is if I knew who the owner was and could trust him/her, or if I knew the vehicle's history from birth. That's just me.

 

Well it sounds like the dealer misled you too. As long as you get it fixed correctly on their dime I guess it's not a giant deal? It's sad that a dealer tech. can't figure this out and has to farm the job out to a speed shop.

Good luck, I feel your pain.

What ever gave you the idea it had aftermarket cams?

 

Yeah that is the part that I do not understand. Just put the car back to oem and get it running. How hard is that?

 

The bama tune, the rough idle, and it sounded like this.

http://s1299.photobucket.com/user/Mi...tml?sort=3&o=1

This is when I dropped it off at the dealer. It was having a hard time starting and had mis-fire codes.

http://s1299.photobucket.com/user/Mi...tml?sort=3&o=0

It sounded like it had cams to me.

 

You had a 2010GT. Traded for a 2015EB4. Now you traded back to a 2010GT that misses so bad you thought it had cams? I think your dealer screwed you over

 

I would be checking for a vacuum leak.

 

It runs great on the highway and pulls real hard for a 4.6. I do not feel a loss of power just when it is at idle it is really rough. You think if it where missing that bad it would be throwing codes right now.

 

So once you're moving it runs ok then? If so then maybe it was just a ghost lopey cam tune. They all sound like they're going to stall out but once you start moving then it should purr.

 

That is correct. However, it has a factory tune on it now. So why is running so bad?

A Ghost tune? I have never heard of that. That might be what is going on. You would think a oem flash would have fixed that.

 

I 'think' Bama never did make a 'Ghost' cam tune. I know they never would for the v6's. I have one i run from time to time on my v6. Who told you it had a Bama tune? If your dealer did, i wouldn't mess with them anymore. Unless they are working on your Mustang 'for free'.

 

I would start with the MAF and then check the throttle body. Always a good place to begin with when it comes to rough idle issues.

Do you know what the misfired codes were? They should have been P03XX if it gave you a specific cylinder, did you try chasing the misfire by moving the COPS?

The 3V's never had a Ghost Cam as you are able to create overlap to make them lope with cams.