My 01, 6 speed the other day sputtered & stammered, then cleared up. Couple days later it did it again, this time the water in Fuel light come on. Changed the filter immediately. Was ow for a couple days then did it again. Took to dealer, they said 0 fuel pressure, changed Lift Pump. Ok until today, sputter and water in Fuel light on again. Have run several tanks of fuel through during this time so I don't think its fuel. Advise ?