I have a 1998 Corolla. In the past week or so there have been 3 or 4 occasions when I am trying to start from a dead stop, I push the gas pedal and it feels like the pedal just goes down, almost like the car is dying. But then it catches and goes on with no problems. This morning it did that but then it died on the side of the road. After that, it would try to start but then would not stay running. Two different part stores said that the fuel filter is not replaceable and that I would have to take it to a dealer to have the fuel pump replaced. Is this true?