Usually a bad idea to keep less then 1/2 tank over a long period of time since temperature changes causes moisture to condense in the fuel tank (and we all know water in the tank is not good). Keep listening, you MIGHT have a foaming issue from the return line or somewhere else. If you do, when the fuel pump catches that foam, it'll cause the pump impeller to spin much higher and starve the rail (if a long enough duration). Don't 'crazy' on it, just keep a listen for it repeating itself. If it does it with 1/2 tank of fuel, you need to look for its cause. Good luck, and have fun cruising!

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