My 89 300 TE has a problem. When my fuel level gets to around 1/4 of a tank, the engine starts to run funny. The RPM's flucuate wildly, and I have to keep the revs up on the engine to keep it from stalling when I come to a stop. As soon as I fill up, the car behaves normally, with the occasional exception of some hesitation on takeoff. The obvious short term solution is to not let the fuel level go below 1/4 tank, but I'm worried that the problem may grow worse and leave me stranded. My guess would be the fuel pump, but I'm really not sure. Any advice would be appreciated. Oh, the car has 132k miles.