A common fail on the 98 era fusebox is losing the connection to the fuel pump relay. This makes the relay operation, and consequently, the fuel pump intermittent. Bouncing it around on rough surfaces are likely to make it happen more regularly. With the engine running, try wobbling the fuel pump relay in it's socket. You'll be able to feel it switching even if it doesn't switch off long enough for the engine to die. If the fuel pump itself is intermittent, which is pretty rare as they will usually work or die, then on a GEMS there is nothing to stop you putting an external pump in the fuel line next to the filter. As long as it is capable of supplying sufficient pressure and flow, the fuel pressure regulator on the fuel rail will deal with the pressure.