check engine still on. Occasional gas smell

[goguenm]

My engine light came on a month or so ago and when checked, code came back as gas tank pressure sensor, got fixed. One week later, light is on again, code is now gas tank purge valve, got fixed. Again, one week later, light comes on. Code is now p0442 for EVAP system leak. Guys did some 'smoke test' TWICE and can't find any kind of fuel leak in system. Put new gas cap on. Light is back on for 4th time now. Still get occasional fuel smell from air vents when I stop for a few seconds at lights. Maybe don't smell when I drive because of the wind (?) Very random. Days will go by and I won't smell it. Some car guys say maybe injector O-rings? EVAP canister failing? Anyone out there had similar problem? Only paid for the first job, did all rest at no charge. But feel what I paid for at first was not actually the problem. Car is '97 cavalier. Never had any other problems. I wish my next car works as good. Car works fine. Nothing noticeable at all in driveability. Just that damn light on, and, unless I'm dreaming, little fuel smell every once and a while. Seems simple enough. Hope you can help.