I was at a long streetlight yesterday and decided to search for my rattling noise. Finally I palmed the gas cap cover and it stopped. The rubber **** at the base are there and everything is tight. I am sure if I search the forum it has been discussed before. Improving the tightness at the hinge is where I am going to go. I wish it functioned like my magic toilet seat.

 

...or the rubber **** have flattened over time and a new pair will work fine. Or source and install a slightly taller pair of them...

 

Yep, bend the tabs on the hinge spring.

 

Mine did that when I got it. Tightened the lock and slightly bent the hinge noise gone. My rubber bumpers are probably shot but no money fix is good with me.

 

Mine was the key lock. The backside nut was a full turn loose

 

Mine was the hasp inside the lock. Had to replace the lock.