Fuel loss mystery

[Dirtbowls]

Hello, got a bit of a mystery. I've filled up my tank twice now and ran out of fuel within 75 miles of noncontinuous driving both times. I have a locking fuel cap so it's not being syphoned, I've placed cardboard under it and climbed underneath and can't find any leaks, and can't smell raw fuel through the tail pipe. It's not lacking power. I'm baffled.

[Z45]

What is it, a truck, SUV, moped, old, new?

[muddkatt]

What is it, a truck, SUV, moped, old, new?

It might be a moped, its not a top fuel dragster or funny car. They get worse mileage.

[Nanotech Environmental]

If it's a GM truck older than about 8 yrs or so in the salt belt, it could be that the metal fuel lines rusted thru & are leaking. They only leak while under pressure. ie. when engine is running.

Start the vehicle up and look underneath see if fuel is dripping or squirting out anywhere.

[silveradosid]

check vacuum line going to fuel regulator, if its wet it is sucking gas threw it and regulator nees to be replaced