My 2002 malibu check engine light keeps coming on. The code indicates that the gas cap is not on. I replaced the gas cap, reset the code and it still comes on after a few days of driving. What else could be the problem? Is there a common problem for this model and year?

 

Welcome to the forum. It would help if you posted the actual code and also your level of mechanical ability. A repair shop will use a professional scan tool and smoke machine to find the leak.

 

The code is P0440

 

That code says a weak vacuum condition. It could be a large leak (larger than a pinhole) between the fuel fill cap and the purge solenoid. It could also be a blocked purge line (lack of intake manifold vacuum). I don't know about you but I myself would take it in to get it serviced. Good luck.