Pay attention to your 'check engine' light
CarMD Corp. has compiled a database of diagnostic trouble codes, car repairs and costs from a network of thousands of certified mechanics who say ignoring a "check engine" light is an expensive mistake.
"Ten percent of all drivers have a check engine light on at any time, and even worse, 50 percent of those drivers ignore the light for more than three months," says Kristin Brocoff, spokeswoman for CarMD.com in Irvine, Calif. "People are fearful of the cost of finding out what's wrong, but it could be minor. Not checking it can impact your fuel economy and have a snowball effect that can cause other problems or even a safety risk."
The No. 1 reason for a check-engine light is a malfunctioning oxygen sensor, which Brocoff says costs $250 to fix. If you ignore it, your gas mileage will decline by 40 percent.
Brocoff says a damaged spark plug is one of the top five reasons for a check-engine light. You can replace it yourself for $10, but your costs can go above $1,000 if you ignore it and need a new catalytic converter.