Expert: Kevin Pilotte - 1/27/2005

Question
Kevin,

First off, thank you for responding so quickly to my question. And yes, my check engine light illuminates but only when going up a relativly steep hill. I had not filled up my tank prior to the problem. I had the day before replaced the air filter. The reason I thought it was water in the gas was because it had rained directly prior to the problem. I had an oil change about 2200 miles before the problem as well. My car has roughly 59000 miles on it. could it possibly be fouled spark plugs or do you think I am looking at something worse?


Joshua
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Followup To
Question -
Kevin,
 I own a 2003 Cavalier base model. And today on my way to work my car seemed to hesitate when I gave it gas and when I was at a stop, it was barley idleing at 500 rpm. I thought that I may have some water in my gas so I bought some STP fuel system cleaner, put it in and filled the tank with gas. What do you think the problem might be?
Answer -
You could be heading in the right direction. However, if the car is performing poorly because of water in the gas or contaminated fuel, adding an additive will not help. The additive can remove some moisture, but not a bunch of water. Dirty or restrcited injectors could create this condition. If you have around 50,000  miles on your car, you might consider having the injectors cleaned. OR if you are patient, continue adding a quality fuel system cleaner to the tank. Did this happen after filling the tank? Is the "Check Engine" light illuminated on the dash? How many miles on your car? Have you had to have any services performed? i.e. spark plugs, filters, etc.  

Answer
If your check engine light comes on, I would recommend bringing it to a competent mechanic. They will have to read the DTC (diagnostic trouble code) and proceed from there. Any one of a number of computer sensors could be bad, thus setting the DTC and causing or contributing to your drivability problem. It still wouldn't hurt to keep adding an injector cleaner to your fuel. Good luck.
Kevin