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Any Ford Mechanics? - 2010 Mustang GT

kthomas

kthomas

Sergeant
Full Member
Minuteman
Jun 17, 2009
8,327
11,476
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Tucson, AZ
#1
Looking for some help on a 2010 Ford Mustang GT.

I'm having an issue with its idle and throttle control. Check engine light is on. Car idles around 700-800 RPMs, and has (until just recently - will explain below) an unresponsive throttle. RPMs wont go above 1100-1200 even if I mash the gas peddle.

I was looking around on other forums about idle/throttle issues, and found a thread from years ago where someone suggested to someone with a similar issue to do this:

Tune would help with throttle response.
also give this a shot

1. Turn on car without starting the engine
2. Wait till most the dash lights go out (seems like two remain on)
3. Step on the gas pedal in one smooth and steady motion
4. Once gas pedal hits the bottom, let go
5. Turn off car and wait 4-5 seconds
6. Turn engine on
7. Drive

Repeat 1-6 if it doesn't work the first time.
Click to expand...

I did that, and lo and behold, the throttle is now responsive and idles around the 1k mark. I have no idea what that combination did, I understand the throttle on this car is electronic, so I'm assuming something was reset? It still has a check engine light on though.

The car was just recently at the mechanics to change out the front lower control arms and struts. I'm not sure if something could've gotten knocked loose or damage during that?

What would cause this issue?
 
#2
OK This is what you need to do.

1. Park the car on a smooth and level surface and exit the vehicle.
2. Make sure the door closes and latches securely.
3. Confirm there is adequate illumination on all surfaces of the vehicle.
4. Ensure the vehicle is secure and will not move "accidentally".
5. Do not open the driver's door or otherwise enter the interior.
6. Verify the car is positioned as above.
7. Slowly walk around the car in a clockwise circle starting at the left front fender.
8. Look for any type of "Ford" logo, markings, or insignia.
9. Did you see any logo, markings, or insignia?
10. That's your problem.
 
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#4
Go to oreillys or autozone and get them to run the codes to see why the check engine light is on. They'll do it for free. DON'T immediately buy whatever parts the code reader indicates is the problem. Need to get it checked by somebody with good knowledge of the system rather than throwing parts at it based on codes alone.

There are many reasons the engine may go into a "limp-in mode". When in this mode, the throttle response is very limited as you describe. I don't see how this has not caused many wrecks in freeway traffic.
 
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#6
Disconnect the battery for an hour. Reconnect and see if check engine light turns off.

Not a Ford, but my Chevy just had a similar problem. Chevy ended up replacing the entire gas pedal, which has a sensor in it since everything is drive by wire. Problem resolved.
 
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#7
Don’t let the retards at auto zone, advance, etc clear any of the codes. If they clear them, it’s gonna cost you a lot more in diagnostics.

A basic code scanner costs under 50 bucks. If you count your time, you’re probably gonna be cheaper going to a good mechanic or a shop that specializes in mustangs.
 
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#10
What you did was "relearn" the electronic throttle control. There are some adaptive parameters that may need to be reset from time to time due to mechanical wear, changes in the electrical characteristics of the throttle body and throttle pedal position sensors, and accommodation of deposits on the throttle body surfaces.

The MIL might be due to a history code, or there may be another actual problem, so I'd recommend getting a code reader on it ASAP. You may have something simple but critical like a defective MAP sensor, or there could be nastier problems lurking within the throttle control system.
 
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#11
I had a similar issue in a similar vehicle. (F150). The throttle body gets gummed by the pcv letting oil into the intake before the throttle. Changing the throttle body and adding an oil separator/catch can is the solution.
Mass airflow is also a likely cause of poor
idle/lack of response.

A OBDii scanner is like $30 on Amazon and well worth the investment.
 
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#12
We have a lot of F250 crew trucks with the 6.7l gas engines. We have to replace throttle bodies and the accelerator pedals periodically. At this point, we replace them both when they start acting up. By the time they need replacing again they’re usually retired out of our fleet with anywhere from 275-350k miles on them.
 
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#13
E. Bryant said:
What you did was "relearn" the electronic throttle control. There are some adaptive parameters that may need to be reset from time to time due to mechanical wear, changes in the electrical characteristics of the throttle body and throttle pedal position sensors, and accommodation of deposits on the throttle body surfaces.

The MIL might be due to a history code, or there may be another actual problem, so I'd recommend getting a code reader on it ASAP. You may have something simple but critical like a defective MAP sensor, or there could be nastier problems lurking within the throttle control system.
Click to expand...

My mechanic is not too far from me, I'll see if they can get it in tomorrow.

I find it interesting that the car goes into limp mode very shortly (like within a week) of them changing out the lower control arms and struts.

I wonder if they bumped loose a connection or something when doing that work? Otherwise I don't know how that work would cause a limp mode.

Or perhaps it's completely coincidental timing, and it's something else, a faulty/worn/broken part like you and others are suggesting.
 
#15
The problem may have absolutely nothing to do with the throttle. It could be the engine temp sensor lying to the computer saying the engine is overheating etc. The computer would then limit the throttle response in an effort to prevent further overheating. If the problem is intermittent then killing the engine and restarting would allow proper response until the intermittent problem reappears. That's why you have to find out why the check engine light is on and work from there.
 
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#16
kthomas said:
My mechanic is not too far from me, I'll see if they can get it in tomorrow.

I find it interesting that the car goes into limp mode very shortly (like within a week) of them changing out the lower control arms and struts.

I wonder if they bumped loose a connection or something when doing that work? Otherwise I don't know how that work would cause a limp mode.

Or perhaps it's completely coincidental timing, and it's something else, a faulty/worn/broken part like you and others are suggesting.
Click to expand...
I’m with you on this one. You just had work done and now you’re having this problem. Maybe the left a sensor or something not plugged in correctly. Maybe a wheel speed sensor or something.
 
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#20
Have the car scanned. You most likely did a throttle relearn, depending on mileage, you might need to clean the carbon out of the throttle body. That can cause o2 sensor faults which is why you need to see what faults you're dealing with.
 
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#22
Can't say shit one way or the other until you post what code is setting the check engine light.
It's like shooting in the dark with no night vision or thermal.....and no moon.

Find out what codes are stored, do not let them reset the codes, post em up.
 
#23
kthomas said:
My mechanic is not too far from me, I'll see if they can get it in tomorrow.

I find it interesting that the car goes into limp mode very shortly (like within a week) of them changing out the lower control arms and struts.

I wonder if they bumped loose a connection or something when doing that work? Otherwise I don't know how that work would cause a limp mode.

Or perhaps it's completely coincidental timing, and it's something else, a faulty/worn/broken part like you and others are suggesting.
Click to expand...
Another check for is any broken grounding connections engine to ground, with the electronics it needs a good ground.
 
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#24
Jsp556 said:
Don’t let the retards at auto zone, advance, etc clear any of the codes.
Click to expand...
Pretty broad and damming statement there. I bet if you paid attention to your local parts houses, you’d find at least ONE qualified guy to work on your car. Not all of them are retardant. I’ve seen more than one shady ass mechanic try to fuck a customer over, and I’ve seen a guy that worked at AZ for 30 years part time just to pull business to his full time auto shop which was very successful and trustworthy.

And I’m pretty sure they will print you a copy of the codes your car is throwing. Take that to a mechanic or do some research on the most common causes of your symptom based off the code. Always helps to have a basic understanding of what the mechanic is telling you.
 
#26
I'm not terribly familiar with Ford gas stuff, but I would generally prefer to pull codes with a "professional grade" tool that might be able to access stuff beyond the usual OBD codes. When you pull DTCs from all the modules and start seeing things like history codes for low input voltage or comm errors across the vehicle, you can get some clues that might not not be apparent from just the current ECM codes.
PXL_20230905_220635217.jpg
 
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#27
E. Bryant said:
I'm not terribly familiar with Ford gas stuff, but I would generally prefer to pull codes with a "professional grade" tool that might be able to access stuff beyond the usual OBD codes. When you pull DTCs from all the modules and start seeing things like history codes for low input voltage or comm errors across the vehicle, you can get some clues that might not not be apparent from just the current ECM codes.
View attachment 8473334
Click to expand...
True, but not errone wants to spent a few grand on a quality reader. Not to mention places like snap on will bend you over backwards after your “cool whizbang” is a few models old and they refuse to support updates on it. My brother has 3 snap on readers, and two won’t read(or do any flash changes) past a certain year model( I believe it is 2017). Sure snap on has a buy back but when has that ever worked in the owners favor.

I forget the brand he said he would probably move to next, but he has been a snap on guy for 20 plus years, and for him to say that is shocking to me.
 
#28
roostercogburn98 said:
True, but not errone wants to spent a few grand on a quality reader. Not to mention places like snap on will bend you over backwards after your “cool whizbang” is a few models old and they refuse to support updates on it. My brother has 3 snap on readers, and two won’t read(or do any flash changes) past a certain year model( I believe it is 2017). Sure snap on has a buy back but when has that ever worked in the owners favor.

I forget the brand he said he would probably move to next, but he has been a snap on guy for 20 plus years, and for him to say that is shocking to me.
Click to expand...

I like the Bosch and it was about half the price of other "big name" brands, but admittedly it's overkill for the average home mechanic. Given the other "investments" that I've made in this stupid hobby, it still felt like a good value.

If I had stricter budgetary constraints, something like the XTOOLS D7 or whatever Autel currently offers in the ~$500 range would be my choice. I don't think they offer pass-thru programming, but they should pull codes from almost all the modules on an older vehicle and aren't subject to stiff yearly maintenance costs. I know this is a lot more expensive than the $50 scanner hanging off a peg at AutoZone, but IMO one has to look at the money being saved by not relying on a shop and investing accordingly in tools.
 
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#30
E. Bryant said:
I like the Bosch and it was about half the price of other "big name" brands, but admittedly it's overkill for the average home mechanic. Given the other "investments" that I've made in this stupid hobby, it still felt like a good value.

If I had stricter budgetary constraints, something like the XTOOLS D7 or whatever Autel currently offers in the ~$500 range would be my choice. I don't think they offer pass-thru programming, but they should pull codes from almost all the modules on an older vehicle and aren't subject to stiff yearly maintenance costs. I know this is a lot more expensive than the $50 scanner hanging off a peg at AutoZone, but IMO one has to look at the money being saved by not relying on a shop and investing accordingly in tools.
Click to expand...
Makes perfect sense to me. I don’t “need” a lot of shit, but there it sits in my gun room.

I agree there are happy mediums on the scanner as well. I do believe my brother has mentioned the brand autel before if I remember correctly. When he speaks car, I hear jibberish that I want to make sense but can’t quite get all of it processed. However I would be lost without a lot of solid advice from him.

Luckily for me, my old beaters hobby cars don’t even have OBD2 ports. Well the 89 might, but I don’t remember seeing it, that should be the year it become common?
 
#31
I remember putting a lot of throttle bodies on Mustangs, Fusions and Escapes from that era. If you have a P2111 or P2112 those are throttle body stuck open and stuck closed codes. If it has either of those put one in it. I would stick with Ford parts. When you replace it you want to reset the KAM (keep alive memory).
 
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#33
roostercogburn98 said:
Pretty broad and damming statement there. I bet if you paid attention to your local parts houses, you’d find at least ONE qualified guy to work on your car. Not all of them are retardant. I’ve seen more than one shady ass mechanic try to fuck a customer over, and I’ve seen a guy that worked at AZ for 30 years part time just to pull business to his full time auto shop which was very successful and trustworthy.

And I’m pretty sure they will print you a copy of the codes your car is throwing. Take that to a mechanic or do some research on the most common causes of your symptom based off the code. Always helps to have a basic understanding of what the mechanic is telling you.
Click to expand...
Yep, a blanket statement. Yep, I meant to cover all of them. If the 30yr mechanic drumming up work behind the counter needs to work there to get business, his work probably isn’t good enough to grow by word of mouth. Apply that logic to the local gun store smith. Take your new action and top end blank and let him have at it.

Any competent shop is going to do their own diagnostics. Auto zone code readers don’t access all of the information stored in the vehicles computer. There are mfg specific programs to diagnose vehicles that only dealerships and paying shops have access to. But go ahead, let the minimum wage kid plug in. Then buy parts till you find what’s wrong. A lot of times an unrelated sensor failure will throw obd codes unrelated to the failed sensor or part.
 
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#36
+1 on the qualified mechanic and tangential equipment throwing codes. The 2013 EB F150 has a chip in the front suspension somewhere (pwr steering? IDK I'm not a mechanic) that trips limp mode when the chip gets too beat up. Replace the part and it all works fine again. Same with the throttle body (whichi is a cheap part and easy to replace).
 
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#39
kthomas said:
My mechanic is not too far from me, I'll see if they can get it in tomorrow.

I find it interesting that the car goes into limp mode very shortly (like within a week) of them changing out the lower control arms and struts.

I wonder if they bumped loose a connection or something when doing that work? Otherwise I don't know how that work would cause a limp mode.

Or perhaps it's completely coincidental timing, and it's something else, a faulty/worn/broken part like you and others are suggesting.
Click to expand...
Anything is possible but I’d find it highly unlikely that the control arm repair had anything to do with your issue. As others have said you need to have codes checked. Typically you’ll get a light on that looks like a wrench when the vehicle is in “limp mode”. Most common things that cause one to go into limp mode are issues that can cause catastrophic failure to the engine or issues that will cause a safety concern. Accelerator pedal position sensors are something that goes bad but not necessarily a known concern. The electronic throttle body is more common. If the PCM sees a command for throttle and then doesn’t see an increase in rpm it’ll set a code and go into limp mode. The APP has two sensors in it’ll that check against itself. One goes from 0-5v and the other from 5-0v. Any discrepancy in this will also trigger a fault. Some aftermarket scanners only pull generic codes and not dealer specific codes. I’d have it checked and get back to us with the actual codes. I have access to all the factory Ford service and diagnostic information if you need any help.
 
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#40
roostercogburn98 said:
True, but not errone wants to spent a few grand on a quality reader. Not to mention places like snap on will bend you over backwards after your “cool whizbang” is a few models old and they refuse to support updates on it. My brother has 3 snap on readers, and two won’t read(or do any flash changes) past a certain year model( I believe it is 2017). Sure snap on has a buy back but when has that ever worked in the owners favor.

I forget the brand he said he would probably move to next, but he has been a snap on guy for 20 plus years, and for him to say that is shocking to me.
Click to expand...
Snap on scanners are good but the licensing is outrageous. We have a pro link ultra for heavy truck and the licensing is about $2k per manufacturer. That’s after we spent $10k on the unit. It essentially useless to us now as my employer doesn’t want to spend the money on it. Luckily we are a fleet and have ford ids/frds, Cummins insite, Freightliner diagnostic link etc. That covers most of our fleet but we still have some odd ball stuff.
 
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#44
Jsp556 said:
Any competent shop is going to do their own diagnostics. Auto zone code readers don’t access all of the information stored in the vehicles computer.
Click to expand...
I’d counter to your novel, but you probably wouldn’t get it. I’m just not that interested in going back and forth with a guy like you. OP seems to have found the problem anyway. Good luck in life, thanks for staying in the fight this long.
 
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#45
roostercogburn98 said:
I’m I’d counter to your novel, but you probably wouldn’t get it. I’m just not that interested in going back and forth with a guy like you. OP seems to have found the problem anyway. Good luck in life, thanks for staying in the fight this long.
Click to expand...
Ok. We’re free to disagree. Best wishes to you as well.
 
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