My 2000 Grand Am check engine light came on a couple weeks ago and I had it tested at Auto Zone and they said it was a small leak in the emissions, probably gas cap. So, I had that changed and three weeks later the light came back on again. So, back to Auto Zone we went and it came up the same code again. Small leak in the emissions there's no visible leaks and the gas cap is tight and brand new. Any ideas on where I could look for leaking or what I can do? Thanks!

P0442? Are you sure the gas cap is being installed fully tight? Three or four click when tightening? There may be a poor connection at one of the vac lines in the emissions control system. Or the vac line has become dry-rotted and leaks that way.

I recommend you go to a GM dealer or qualified ASE certified shop and have the problem thoroghly diagnosed. Get an estimate and ask about their warranty.

Good luck.