Car driving itself???

Topic: Car driving itself??? (Read 1552 times) previous topic - next topic

Car driving itself???

May 27, 2006, 10:46:29 AM

About two weeks ago my car started driving itself. When I would depress the accelerator, it would act like it was stuck when I let off of it. Now it has gotten to the point where it will speed itself up. It become very dangerous and I'm sure it's tearing up my brakes and transmission. I was wondering if anyone had any ideas to what the problem might be. It doesn't really do it at any particular time, but I thought it might have been the transmission as I just had it rebuilt. I don't believe it is now, because it acts like the accelerator is down, revving the hell out of it, even when I put it in neutral. Any help is appreciated.

Car driving itself???

Reply #1 – May 27, 2006, 11:00:08 AM

I dont have any help, but my friends car drives itself, there is nothing wrong with the car. I have driven it. Whenever we venture into the country to a place where someone died racing his car, it revs and starts to literally drive itself. I have been trying to get video of it, its messed up to watch the gas pedal move itself.

Car driving itself???

Reply #2 – May 27, 2006, 01:33:26 PM

Throttle position sensor.

Car driving itself???

Reply #3 – May 27, 2006, 02:12:49 PM

I kinda thought that was what it was. I mentioned it to the "mechanic" and he replaced plugs, wires, fuel filter, and cap. All of which I did 8 months ago. I suppose I may just not pay him seeing as he tried to stiff me. Well, now I guess the only question is how I replace it. Hayne's has nothing and I've already searched the forums.

Car driving itself???

Reply #4 – May 27, 2006, 09:58:24 PM

sounds more like a cruise control problem to me,, thats the first thought that hit me. if the pedal moves on its own,, theres no way a tps could control the physical movement of the gas pedal. The accel function could however if there is a malfunction in the cruise control circuit or an intermittant short

disconnect the cruise control and go from there is my opinion.

the second thing that comes to mind is the base plate of your CFI,, if there is a vac leak there, you will experience a high rev of rpm's and the car will lung or lurch forward like the gas was depressed. This is prob not the case because you said your gas pedal seems to say put when you let off it.

Car driving itself???

Reply #5 – May 27, 2006, 11:40:54 PM

Quote from: Tbird232ci

Throttle position sensor.

I agree. I had the same thing happen to me, and a new TPS solved the problem.

Car driving itself???

Reply #6 – May 28, 2006, 12:24:40 AM

another thing since your a CFI system ,,, the idle control motor may be the culpurt. Its plunger will physically extend out and hold the trottle open which is directly controlling your gas pedal movement.

soooooooooo..................

if you assume its good,,, the idle control motor does get one of its signals from the map sensor.
unplug it prior to turning on the key. start and drive with it disconnnected and see if the problem still happens as well.

Car driving itself???

Reply #7 – May 28, 2006, 12:39:59 AM

My CFI overidles and drives itself all the time. I usually just rev it once or twice and it calms right down. I am not too worried about it though, because I am switching to a Holley 650 CFM 4 BBL Carb Soon enough.

Car driving itself???

Reply #8 – May 28, 2006, 01:15:16 AM

Well the cruise control is not hooked up, and the fuse to it blew before I disconnected his cruise, and his car is carbed, so I dont know if the choke to be wierding out or what

Car driving itself???

Reply #9 – May 28, 2006, 10:02:35 PM

Cougarrr302 are you talking about Sscobrapride's car?

I had a problem with my '84 3.8L T-Bird that sounds like your problem. Very slow to return or not returning to idle when getting off the gas.

With the engine not running the throttle linkage had plenty of spring tension to pull the throttle plates closed.

With the engine running I had very little spring tension. Yes I disconnected the cruise and trans kick-down (C5).

The linkage has to press hard enough on the ISC motor plunger tip to make a contact inside the motor called the ITS (idle tracking switch). This switch closing tells the EEC that it is in control of the engine speed.

Never could figure out why the spring tension decreased so much with the engine running.

I drilled a little hole in the corner of the throttle linkage pad that presses on the ISC plunger and added a spring.
The other end of the spring goes where there is another spring, I think it's for the C5 trans kick-down. If you have AOD it may be different. I put the spring inside some plastic tubing so they wouldn't rub each other.
It's been solving my problem for about two years now.

Car driving itself???

Reply #10 – May 29, 2006, 01:52:27 AM

No im talking about my friends 83 cutlass

Car driving itself???

Reply #11 – June 07, 2006, 10:22:45 PM

So how bad is replacing the TPS. I took it to the shop and the idiot tried to tell me it was a vacuum hose, which leaves me to believe hes just trying to milk me for cash. I know it isn't a vacuum cause I went through all of that, and when I asked him about it, he was kinda sketchy about the details. I'd like to do it myself if it isn't too bad. I really don't want to go to the local dealer and get raped for labor so I'm hoping the 50 it costs for it is all I have to pay. Can anyone give me a run around on replacing the TPS?

Car driving itself???

Reply #12 – June 07, 2006, 10:59:44 PM

To replace the TPS it is simple. remove two bolt/screws remover the
TPS then install the new one. Make sure you use a multi meter to set the TPS so its reads .94-.99 volts with the key on engine off. Use the Green and black wires I think doulbe check the wire colors by doing a search on this site. Hope this helps