My niece’s 1997 Chevy Cavalier had a problem. It would just stall out, somewhat randomly.
When we first got the car, I hardly noticed the problem. Over the next few months it got worse, though, and the problem eventually progressed to the point where the car would stall at least once a trip in city driving. It wasn’t unusual for the car to stall three or four times a day.
Every stalling problem is unique, so the first thing you need to do is diagnose when the car stalls. This will help you figure out what’s going on.
My Stalling Problem
I took my niece’s car for the week so that I could drive it and see what it was doing. Over the course of the week, I noticed a few trends.
The car only stalled when I was pulling up to a complete stop. This often happened at red lights and stop signs. However, it could also happen in bumper to bumper traffic.
After a while, I noticed that the car seemed to stall at the moment when it went from moving to a full stop. Shifting from drive to idle seemed to be a real problem.
The car never stalled while it was moving. It never cut out while driving.
The car would always start back up. Sometimes the start was hard – the car turned over a few times before the engine started – but there was never a problem with it restarting. If I put the car in park, turned the ignition off, waited a few seconds, and turned the ignition back on, I was always confident that the car would start.
So What Was the Problem…?
Turns out the problem was in the throttle.
This controls the air intake of your car. As you press down the accelerator, the throttle opens to allow in more air. It also has a sensor that tells the engine how much air is coming in, so that the fuel injectors can provide the proper amount of gas.
I cleaned out the main body of the throttle to no avail. I later changed a sensor (the Throttle Position Sensor) that had given out and signalled a Check Engine Light. Still, the car stalled.
Finally, I cleaned out the Idle Air Control Valve. The valve is designed to move in and out, allowing air into the throttle when the car is idling and closing at other times. A build-up of carbon and gunk had caused the valve to stick. When the car attempted to move into idle, the valve would sometimes not open… cutting off the air and causing the car to stall.
It’s a fairly simply procedure to clean out the IAC valve. However, we’ll save that for another article on another day.
But, if you have a similar intermittent stalling problem, that’s the place to check. As soon as I fixed the IAC valve, the car worked beautifully.