Acceleration Pedal Issues

chrysler
acceleration
lebaron

#1

One of my cars, an 1987 Chrysler LeBaron GTS, which originally belonged to my mother and has all but 30,000 miles on it, on occasion while driving the accelerator pedal will go to the floor. (My mother took excellent care of the car - garaged -so much so that it looks factory new.) The first time this happened to me was last winter when I was coming off the exit ramp of the interstate and it was a long downhill ride to the light. I lightly put my foot on the accelerator to keep at the 30 mph exit speed and suddenly the pad went right to the floor. As soon as I applied the break the car slowed down. It freaked me out but I chalked it up as an anomaly due to icy roads, even though the car had on studded snow tires (2 years old). Then a few months later it happened again while on the highway. I immediately took it to my mechanic who could find nothing wrong - not even the floor mats were in the way. Despite that this still happens and has been increasing in frequency, to the point where I no longer drive the car. Today, my sister went on line and read that the first sign of a transmission going is when the accelerator pedal goes straight to the floor. Is it true that this can happen on a car treated so well with such little millage? If yes, can anything be done short of replacing the transmission? Quite honestly, I don’t want to waste money on a car this old and will sell it to a collector instead. But, I happen to like the car and the way it handles, so would prefer to keep it if it doesn’t cost me an arm and leg to do so. Any other that can help me figure this out? Thanks for any advice and ideas.


#2

I wonder if a defective motor mount is allowing the motor to shift, thus pulling the accelerator cable.I don’t think this car is a drive by wire.


#3

The transmission cannot take control of the accelerator pedal.

When the accelerator drops to the floor does the engine accelerate or does this take away your ability to accelerate, like a disconnected accelerator cable? How do you restore the pedal to normal height?


#4

“has all but 30,000 miles on it” ??

do you mean it has 30k miles on it?


#5

slightly off topic but this is a front wheel drive and are you saying you have studded tires on the front and you are driving on the highway ? If so that sounds like a disaster ready to happen.


#6

Triedaq - motor mounts were checked and they are fine.

Nevada - when the pedal goes to the floor the car accelerates. No problem breaking and bringing the car under control.

BillRussell - Yes, 30K

Volvo V70 - In the winter studded snow tires are on all the wheels, not just the front.


#7

Nevada - also the pedal goes back to normal on it’s own.


#8

Phantom pedal just drops away from your foot? Is this a 2.2L turbo?


#9

Does the vehicle have cruise control?

Tester


#10

Yeah, we are having trouble understanding exactly what happens.

The petal goes to the floor without your pushing it ?
When does it come back ? immediately? on it’s own?
Or do you mean the resistance drops to zero, so your normal pressure makes it move to the floor?


#11

No, the pedal goes to the floor when I depress it to increase speed. I just found out what the problem is on another forum and thought you guys might like to know what it is.

Tester - you were on to the right problem. It has to do with Cruise Control. I didn’t even know I had it on this car as I never bothered to read the manual and where it is located isn’t where it is on my other cars. The turn signal on this car also has the windshield wipers, and to the right of that is cruise control, except it’s called speed control, and it was in the ON position. Would that be the reason, after decelerating off a highway from 65 to 25 then depressing the accelerator to increase speed would cause the pedal to go to the floor? Sounds like the Speed Control is doing that and trying to bring the car back up to speed because it says in the manual the original speed would stay in memory after I pressed on the brake. Only turning off the Speed Control would the memory be cleared. Thanks guys. I’m going to drive the car around for the next week or so and see if this problem returns even with the switch off. Somehow I think this has been the problem all along.


#12

The “set” speed is only in the memory for one ignition cycle, the next time you start the car there will be no reaction when you push the “resume” button. You cannot engage, set or resume the speed control at speeds below 35 MPH (unless your vehicle speed sensor is failing).

I have seen a few malfunctioning speed control switches that the “accel” button gets stuck, however it will take 15 to 20 seconds to reach 1/2 throttle, full throttle is unlikely and applying the brake shuts off the system.

If you are pushing the accelerator to the floor as you stated is there a problem? Will the pedal not return? Is it getting stuck to the floor?


#13

The OP stated, “As soon as I applied the brake the car slowed down”.

Applying the brake causes the cruise control to disengage, And that’s why I was going there.

Tester


#14

Yes, I thought it was odd that the car could be easily slowed at full throttle. He didn’t make it clear that the throttle released when applying the brake.


#15

Glad you got the accel pedal problem resolved OP. Even though your car only has only covered 30K miles since 1987, that isn’t the same as a 2012 with 30K miles. Some components need to be replaced on a time basis as well as a miles basis. Rubber and plastic components like belts and bushings for example. Filters and fluids too.


#16

Nevada, I think I didn’t make myself clear. When I put my foot on the accelerator it felt like it was moving down on it’s own - fast. It’s a freaky feeling on a car you don’t think has cruise control. I could hit myself in the head over this because I have 2 other cars with cruise control and the few times I’ve used it experienced the same feeling but didn’t freak because I expected it. The position of where the cruise control is on this car is unusual. On my other 2 cars they have their own dedicated spot that can’t be unintentionally engaged.


#17

If the cruise control switch is malfunctioning the cruise can engage or accelerate, sometimes when the turn signal switch is moved. This will cause a gradual tip-in of the throttle, not a 5000 RPM full throttle trust. If you could clarify or demonstrate this for your mechanic he might go straight to the problem and have a solution

I’m still curious if you have the turbo engine, that will thrust you down the exit ramp quite well.


#18

Nevada, I don’t think it is a question of the cruise control switch malfunctioning. I think it has to do with where the switch was located and my accidentally putting it on. I don’t have a turbo engine on this car, as far as I know. What I know for sure is that the cruise control was in the ON position. According to the manual, I would have to push the control slide to the Resume position to reengage the system. But, as I didn’t even realize this car had this feature I never did that. All I can assume is that I did something when using the wipers which is also where the control is located further up the same stick. According to the manual ‘when you reach the desired speed you move the control to the ON position. This will establish memory and activate the system’. But the manual also says that breaking will deactivate the system without erasing the memory and I would have to push Resume to reactivate Speed Control. Only by ‘Pushing the control to the OFF position or turning off the ignition erases the speed memory’. According to the manual the system only activates at 30 mph or above. But you are supposed to put the switch ON when you reach the desired speed for the system to engage. I don’t know if it would engage itself by just having the switch in the ON position simply by turning on the car. One of the things the manual says that has me thinking is ‘A sudden increase in engine rpm may be experienced if the clutch pedal is depressed while the speed control is engaged.’ If that is the case can I assume that would cause the feeling that the accelerator pedal is moving down faster under my foot than I intended when I lightly depress the pedal?


#19

You have to do things to activate any cruise control. 1. turn it on. and 2. hit the set or resume button. So if you only turned it on, it would be inactive.

If you have a manual transmission, usually depressing the clutch turns the cruise control off. Apparently your car does not have this safety feature. So if the cruise control is active, trying to maintain a set speed, and you depress the clutch, the cruise control will attempt to maintain speed by increasing the throttle setting, which does no good. So yes, you could see the acc. petal go down if you release the clutch.


#20

Thank you Bill. Since this is an old car I am assuming it lacks the safety feature you mentioned. Only one real way to find out and that is to start driving the car again. If this happens while the Cruise Control is in the off position than it will be back to square one. I’ll keep you posted if it happens again.