ok, my gf has a 99 2.2l auto cavi. she's called me a few times almost in tears because her car takes off for no reason. she says sometimes it will just rev and go and she can't stop it by holding the brake. she's gotten good at putting it in nuetral and shutting it off but it's not safe so i've got the car to drive for the week. this has happend at no particular time in the driving cycle. it's happend at lower speeds between 0 and 20mph. once it happend while she was stopped at a light with her foot on the brake. the only thing i could come up with is the iac acting up. i thought maybe the tcc might be locking up but that doesn't explain the rpm spiking. the throttle cable and throttle body operate freely. she doesn't even have cruise control. any ideas? ever heard of this?
*stop drop and roll won't work in hell.*
my friends cavalier is doing something like that. she can be stoped and then the car will rev itself yup and it will jerk and try to move but she stopes it. or it just shuts off. we still cant find out whats makeing it do that.
for it to be inconsistent is odd.
i have two theories.
1.) Like you said, IAC, that is one of the few devices that controls idle and is out of your control.
2.) Could be a faulty intake manifold gasket. I've seen this before, but it was consistent. you can either hook it up to a smoke machine (not practical). Or with it running, spray some intake cleaner around the gasket surfaces. if you are spraying, and the idle just goes nuts, you've found it. also, take caution not to drip onto the exhaust and start a fire.
my gf described what jbody03eco said. at a light and it starts reving and jerking. no stall yet tho. i'm hoping to get it to do it for me sometime this week. i thought of the intake gasket leaking too but the inconsistancy doesn't make sense. it would be more heat related. i drove it today twice for 20 min then about an hour with no trouble at all. unfortunately i can't watch the iac on my scan tool. the complete randomness leads me to believe it's something electrical. any other ideas?
*stop drop and roll won't work in hell.*
Yes, I have seen this before and corrected it before.
The TPS sensor was the culprit both times, watched it on the scan tool.
The one time it was misadjusted, and the throttle would be slighty open, but the TPS would say about double what it actually was.
The other car was a Lincoln, that did it almost all time, but at stoplights, it would lurch forwards on its own. Turns out that was the TPS to.
- 2004 Cavalier - 124k, owned since new
I read a story from a few years ago of a Sunfire here in Denver that took off on the freeways for a couple hours...turning off the car, hitting the brakes, shifting out, nothing would work. Car was stuck in overdrive. A week later the car was in a garage getting checked out, with the engine running. The car put itself into gear, and pinned a mechanic against the wall....
Quote:
The car put itself into gear, and pinned a mechanic against the wall....
That Sucks.
But yeah...
Sounds like a faulty Intake Mani gasket or a major vacuum leak
Also... (Maybe) It sounds like the ECU took a vacation to Walt sh***y land without you.
Or could be something as small as a stuck throttle body plate, or stuck cable amongst the cruise control.
Hoep it hleps...
...They just HATE it when you ...POINT - LAUGH - then DRIVE OFF AND AWAY-!...
yeah, i'm thinking it's probably the tps. i asked another tech today and he mentioned the same thing. the iac runs off the tps so if it's getting false readings from the tps it could very well run the idle way up. thanks. i'll watch the tps with my scan tool right now. i'll let ya know what i find.
*stop drop and roll won't work in hell.*
replaced the tps sensor and she hasn't had a problem since. i'm guessing that fixed it. makes sense. thanks for the help gents!
*stop drop and roll won't work in hell.*
mine used to do that, my throttle cable kept getting stuck and i sprayed it with white lithuim greese and no problems since. good luck in fixing.
I think this was a story and movie called Christine by Steven King.
go with the IAC... Ive had this happen to me with a 97 2.2 and a 98 2200....IAC. With the 97 2.2 I lucked out, just cleaned the old IAC with brake cleaner popped it back it and voila. if not you just have to pick one up from any local car place. Usually they run about 97+ dollars for it. Unless your like me and Get every part from the Junk Yard
