Questions and Answers
Chevy Cavalier Idle Problem And Flickering Lights
Q. Hi Vince, I have a 1990 Chevy Cavalier Z24, 3.1 litre V-6 engine, automatic transmission, with approximately 260,000 kilometers on it. It has fuel injection, not sure about the ABS brakes, it has power steering, A/C, cruise control, and not sure about the rack and pinion steering.
I actually have two problems, but I am not sure if they are related in any way. My first one is I noticed that when I start my car in the morning, my lights on my car will dim slightly, then brighten up, dim, then brighten. This only seems to happen when I first start the car and she is warming up, Afterwards when she is warm and at idle the lights don't fluctuate.
My other problem is: In the last couple of days I have noticed that my car is running at a very low idle, when in park, as well as when in gear but not moving. The RPM fluctuates between about 500 and 750 RPM when not moving, and when the RPM drops, the car sometimes stalls out on me.
I just finished replacing the drive belt, water pump, tension pulley, and thermostat on the car, and have had my battery and alternator checked. My father suggested I add some of the more expensive fuel injector cleaner into the tank to clean out any build-up, but I am concerned that this may only be a short term solution to my problem.
I do not know when, or if, the injector or fuel filter has ever been changed, and am not sure about much of the history of the car. Does this sound like I have a clogged filter or injector, or could it possibly be something else completely.
Your help would be great, thanks!
A. If you are not sure of the "state-of-tune" of your car, you need to find out. A car with high mileage can have all sorts of problems if the plugs, air filter and fuel filter are worn or clogged.
If there is doubt, do a complete tune-up; spark plugs, ignition wires, air and fuel filters, so you know, for sure, the basics are good.
The flicker of lights bothers me. This would indicate that the alternator may not be charging when cold or you may have a loose or dirty connection at one of the battery cables.
If you were to disconnect the battery, the idle would fluctuate normally until it taught itself how to idle properly. So a loose connection needs to be cleaned and re-tightened. Then let the car idle in gear until the coolant fan comes on. Then shut if off for 1 minute and re-start and let it run for another 5 minutes in gear. This should help with the idle.
And before you do any of this, have the throttle plate and body cleaned of any carbon and coke deposits. DIY: Cleaning Throttle Bodies Good luck!