I have some sidelight markers that like to flicker, as the wedge bulbs just do not sit tight enough.

Highwaystar, I don't think just banging on the tank will free a stuck float if that is indeed the problem. GM and BMW prescribed a bottle of techron in the tank to free up sticky floats on their early millenia models.

Others report that some Marvel mystery oil in the Gas at 4 oz per 10 gallons works as well.