How to troubleshoot p0442 small leak detected

[MissSaturn210]

Hello. I have a 2005 Saturn Ion 2. I have lived with this p0442 code since June, long enough. Code was first scanned at autozone, I was told replace purge solenoid and vent valve solenoid. (done) Check engine light comes back. I took it to the dealership in July. They replaced my fuel tank pressure sensor. The light came back. Dealership didn't offer any suggestions or shine a light on anything else EVAP related. What else should I be looking at? Oh, I forgot to mention I have replafced my gas cap twice and the dealership replaced it a 3rd time. Prior to changing gas cap, I hadn't received check gas cap message until last week. It comes and goes, and not necessarily after fueling up. Thank you for having me! Suggestions highly appreciated!