Q: My 1999 Pontiac Sunfire coupe is doing something something I can't easily explain. The car has 240,000 km on it and it has the stock engine, although I think I bought it with a K filter charger.

Ignoring a check engine light might feel harmless if the car still runs smoothly, but the warning signals more than a minor inconvenience. Driving with that light on can lead to higher repair costs, ...