'99 Malibu 3.1 - the 'service engine' light came on, and the code was 0442. Can this be reset by unhooking one battery cable for 10 minutes or so? PS: I know the problem is that I installed a different (used) gas cap, and the light comes on about 1 day after fueling up. Thanks.

If you fixed the gas cap problem, the light will shut itself off in a few days or so. Disconnecting the battery has never worked for me on the Malibu.