My girlfriend drives a (I think 1992) Toyota Corolla hatchback automatic. She’s been having this problem where she would stop at a red light, and when the light turns green the car would turn off, and she’d have to start it up again.
She says she was not hitting the gas pedal hard, and that it seems to happen more often on or after a rainy day. She also tells me that she’s recently replaced sparkplugs and wires.
Any ideas of what we might be able to do would be appreciated!
Is the engine idling at the usual RPM? If not clean the throttle body and idle air control valve.
Next thing to look at is the throttle position sensor. Make sure that the throttle closed switch is making contact. Measure the resistance of the potentiometer end to end for total resistance, the sweep arm for correct resistance at both ends, and that the sweep resistance to the high end is smooth as the throttle is opened.
BTW Is the Check Engine Light ‘on’?
Get back and we can go from there.
Is this engine carbuerated? Could it be leaking and when it sits for a but and she then hits the gas, it dumps a whole bowl of gas?
Ahh, I think I missed out some pieces of info there.
No check engine light — that said, her dashboard lights don’t work, so there’s no telling if it actually ought to be on.
Also, this doesn’t happen all the time, the last 3 months maybe 3 or 4 times it’s happened, of course it’s at an intersection so she freaks out a bit.
The car doesn’t have an RPM gauge, and I drove it around last weekend; as far as I can tell, the engine sounds fine and drives well. Unfortunately I don’t drive her car much so I don’t have a baseline comparison.
As for the throttle position sensor and such I’ll send her to the mechanic and see what they find.
Thanks for the great info!
Will
Intermittant problems are the mechanics curse. I had a similar problem with my 85 toy truck, and it turned out to be a loose wire from the magnetic pick up in the distributor, but the loose wire was not inside but between the distributor and the igniter. I would have to get out and wiggle the wire to get good contact, and then it fire up again. I replaced the connector and have had no trouble since. So next time this happens, have her open the hood and wiggle the wires to see if she can pin point which wire is bad. I suspect this is it, because the car obviously has the age and other wiring problems such as the dash lights failing. While you are at it, I suggest you check and clean the battery terminals and lugs.
If I’m correct, if the engine is stalling when she hits the gas, then what may be happening is a sudden “lean out”. The throttle body is opening allowing much more air, but the injector is not immediately responding with much more gas.
Researcher hit the nail on the head by suggesting the throttle position sensor. It may not be sending the proper signal to the ECU when she hits the gas. This signal, combined with sudden signal changes from the Manifold Absolute Pressure Sensor and the Mass Airflow Sensor, are what tell the ECU to provide more gas. I’d add the MAP and the MAF signals to the list of things to check.
I believe the '92 was throttle body injected. The only reason I mention this is that if the injector is faltering or the fuel pressure is low that could cause it to be unable to respond properly by maintaining fuel pressure while the injector pulsewidth suddenly increases, and that’s also a possibility. But this one is a low probability. Very low IMHO.