2003 Volkswagen Jetta Sputtering and occasional stalling fu

My Jetta will sputter and sometimes stall when the fuel gage reads below half tank. I have used the mileage counter to see if the gage is not correct, but the level seems true. I would also measure fuel quantity by the amount going in on a refuel. There is no engine light. Again it only happens when fuel level is below half tank. Very Puzzled and wondering if you have any ideas?

Replaced fuel filter and air filter