Fuel Issue

[krs2230]

Hey guys,

I'll try my best to not make this too long winded. I have a 99 Boxster with the 2.5 motor. The car has 154K on it, but great shape, four owners all checked out on Car Fax. Car has run beautifully until two weeks ago. Suddenly it started missing, radically. Seemed like it was not picking up fuel. I took it to my boys who work on her for general maintenance, they thought it was the sensor for coolant temp that was bad, replaced and no change in the performance. At this time the 986 had 1/4 tank of fuel. I drove it for a few days and the worst occurred. It started sputtering and missing to the point where I had to have it towed back to the shop. They then put in a new Mass Air Flow Sensor with no change. I took it to the Porsche Dealer here in Oregon and they found no errors in the computer and told me to drive it until the check engine light came on again. In the meantime, I filled the car full of premium fuel, injector cleaner and octane booster. It ran perfectly for two days. When I reached 3/4 tank full, I refueled. Here is the key, the second I drove out of the gas station, it sputtered like crazy! Now, it runs, but not well. No one can determine what is wrong. Any advice?