I own a 1999 Chevrolet Malibu. I recently had my check engine light come on. I took it to Auto Zone and they hooked it up to their code reader. It came back as P0440, which is an evap code. The guy there told me that it could be a bad gas cap. I located an ac delco cap from acdelco.com, replaced it and the light went out within an hour. I hope this post helps anyone with a similar problem. the part number is GT261.

 

Good info. I'll give it FAQ status so it will stick out in a search.