[TexasLS1]

One question I just thought of - is the cap loose because the thin, crappy rubber gasket cracks or is too thin to seal when the cap is tightened?

I've had to cut my own gasket in the past from a thicker sheet of Buna and that worked very well for a long time - and no spills when I'd take a right turn with a full tank of gas haha! The rubber in new gas caps never last long for me. I guess it's typical of dry fuels nowadays and poor quality of replacement parts?