What besides the Fuel Cap will put in the Info Center Fuel cap but no codes. on 2004 Chevrolet Colorado

The Info Center on this 2004 Colorado z71 4x4 says "FUEL CAP" but I replaced the fuel cap twice, that did not help. The truck smells like rotten eggs.It has NO CODES. Could it be the EVAP purge Valve/control solenoid?

Asked by for the 2004 Chevrolet Colorado
it says that because it has a gross air leak. you need a shop to do the real diag with a smoke machine, scan tool and a voltmeter. then, they can tell you the failure and give you a bid.

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if says fuel cap make sure it tighty put on