Throttle stuck open!

[Grey Ghost]

Alright guys, It's been awhile since I've posted lately, but I've been having some recent issues with my stock 2011 GT. In the last couple of weeks, I have had a few instance where out of nowhere, it seems my throttle gets stuck open and tries to max out my RPMs by redlining uncontrollably.

So far this has happened in a few instances:

One night when i started my car from a cold start in neutral, the gas pedal immediately dropped to the floor and the car redlined and I had to turn the key to shut the car off because it wouldn't stop. I started it back up again and it immediately went right back to redline and I shut it off again. Third time after a a few minutes it started up fine and was back to normal.

Second instance, I was driving on the highway pushing on the gas (not crazy or anything) and the pedal dropped to the floor and the engine worked it's way up to redline by itself. I had to shut the car off while I was going about 50mph on the highway and coast it to the shoulder. I started it up again and it went to redline. Third time, I started it and it started fine.

Finally, just this last weekend, I was driving it again and went to push on the gas pedal a bit harder (again, nothing like stomping on it or anything) and it went to redline. I had to shut the car off, once more to get it to stop and started it back up again like 5 mins later and it was fine.

Now, I've not heard or read anything like this happening on any 2011 mustangs let alone Mustangs period. Have any of you guys encountered this on a stock 2011 GT? or does anyone have any idea as to what the hell is going on? It's like I'm driving a possessed car or some piece of crap Toyota Prius or something!

I'm going to take it into the shop this coming Monday, but would love to know what the hell is wrong with it. Please help!

thanks in advance!

 

[BadHabit2Break]

Have you checked the connections on the TB to make sure they are good? Unplug it and plug it back in.

I know you said it was stock, but have you cleaned the engine bay recently?

 

[stkjock]

Are u certain the pedal is actually moving to the floor? These cars are drive by wire.

 

[Grey Ghost]

Have you checked the connections on the TB to make sure they are good? Unplug it and plug it back in.

I know you said it was stock, but have you cleaned the engine bay recently?

I haven't checked the connections, but the engine bay is really clean.

Are u certain the pedal is actually moving to the floor? These cars are drive by wire.

Yeah I know, that's what I thought was so strange. I know the gas is electronically controlled, so when it dropped to the floor, I was like wtf? I'm assuming there would be something wrong with the electronic connection or something shorting out maybe? or maybe the stock tune is wigging out?

 

[stkjock]

If the pedal is actually moving IMO, it has to be mechanical in the pedal assembly, however the TPS, could ve bad and sending a bad signal to the PCM.

 

[zeroescape]

Im with stkjock on this. The pedal should not be able to fall freely. So i think the problem should be mechanically in pedal. Ie return spring or something.

 

[46Tbird]

There is no mechanical connection from the pedal to the throttle body, so...

From your description, the issue is the pedal movement; the high revs are just the computer and engine reacting appropriately to this throttle input.

So what is causing the pedal to move? It doesn't make much sense, since there isn't really anything that CAN cause the pedal to move down there. Maybe a floor mat came loose? Maybe your new pair of shoes are too wide?

 

[Grey Ghost]

If the pedal is actually moving IMO, it has to be mechanical in the pedal assembly, however the TPS, could ve bad and sending a bad signal to the PCM.

Hmm, If the TPS is sending a bad signal to the PCM, would the pedal move like that? Just curious.

Im with stkjock on this. The pedal should not be able to fall freely. So i think the problem should be mechanically in pedal. Ie return spring or something.

I agree. Are their springs in the gas pedal assembly or something mechanically that could get stuck?

There is no mechanical connection from the pedal to the throttle body, so...

From your description, the issue is the pedal movement; the high revs are just the computer and engine reacting appropriately to this throttle input.

So what is causing the pedal to move? It doesn't make much sense, since there isn't really anything that CAN cause the pedal to move down there. Maybe a floor mat came loose? Maybe your new pair of shoes are too wide?

Your right, it doesn't make sense, but I can assure you it's not a floor mat or a new pair of shoes, because it happens automatically and at random, not everytime I start the car.

 

[stkjock]

He pedal works on way only, it sends a signal to the pcm to command the TB to open, them the TPS signals its position to the pcm. At least that's how I recall it working.

So no the pedal will not move from a bad TPS signal.

 

[char259]

stuck floormat?? Remember Jason saying this happen to him once on a quarter pass

 

[nasty281]

On my 3v I had a bad tps sensor and my revs would stay elevated or rise slowly to 3-4k after letting off the gas. My money is on the tps

 

[walker2t]

I say sell the car it's haunted!

 

[86GT351]

Look into any shops in your area that can do a proper Fuel Injection/Throttle Body Service. If the Throttle Body Service is done properly, it can clear alot of issues up.

 

[Wes06]

its gotta be something in the pedal assembly, ive taken mine out and put it back in, it has springs to give pressure and return the pedal to normal, if it drops to the floor its gotta be that spring acting up somehow or something physical in the floor board catching it somehow

 

[saleen07gt]

This sounds like a problem Toyota was having. I'll bet Ford replaces the throttle body and reprogram the pcm. Was the car setting any codes ?

 

[Sky Render]

He pedal works on way only, it sends a signal to the pcm to command the TB to open, them the TPS signals its position to the pcm. At least that's how I recall it working.

So no the pedal will not move from a bad TPS signal.

It's a little more complicated that that; the PCM inteprets the throttle position, commands a specific torque number, and alters a number of engine parameters (spark, cam timing, fuel, actual throttle opening, etc) to meet that torque target.

That being said, you're totally right that there is zero mechanical connection between the pedal and the TB. I'd replace the entire pedal assembly, stat.

Sent from my toilet using Tapatalk

 

[hawkeye18]

There has to be an external cause - a spring cannot unseat, then reseat itself, then do so again more than once. A spring either works or it does not work. Check carefully for things snagging or hooking on the pedal assembly.

 

[weather man]

Had a bad TPS on a Ford LTD. You would press the throttle with no accel and wham! full throttle. Didn't do it all the time, so quite exciting when it did.

 

[marcspaz]

Mike, There has to be some external force pushing or pulling the pedal. The pedal is literally a potentiometer with a return spring. There is no mechanism, vacuum or motor that can move the pedal assembly down without physical input. The spring only lifts the pedal up.

Some cars have a mechanism that changes pedal position when the car has the cruise control set, but the 2011 GT is not one of them.

 

[blue streak]

I would replace the pedal assembly.