I am 300 miles from home on a road trip, had put 900 miles on the car in two days, was cruising along today when all of a sudden the car started sputtering, much like missing a cylinder or two, until there was no response to depressing the gas pedal, and within one minute of this it stalled. Waited 15 minutes considering my options, started it up, started fine. Drove to gas station and looked things over, checked all fuses, replaced no. 6 which was broken (brake lights/shiftlock). OBD says 2-3-2 but it has been saying that for years. Finally disconnected the O2 - at least I think, car started right up, very smooth. Went 20 miles, same thing happened again. Waited 10-15 minutes, turned around, car drives smooth as silk and very strong, 20 miles later, it happens again. Limped it back to Savannah like this, 15-20 miles at a time.

Bad thing is, I am now at the mercy of the local Volvo dealer.

Recent repairs (about 1500 miles ago): tune up (wires, plugs, rotor cap, air filter), exhaust header pipe, flame trap.

Any ideas?

Also, when I turn on the ignition I can hear the fuel pump in the back making a weird noise (seems to be coming from the left rear of the car). It's different from the noise it used to make when it comes to life with the ignition.