I had some trouble with a 98 Tracker this summer.
It was a pain in the butt to trace.
It would start and run fine. Sometimes it would not re-start after you got to your destination. Sometimes it would. Very unpredictable.
It would crank, but not start. It turned out I wasn't getting fuel.
Replaced the pump and relays, still couldn't depend on it.
Started checking connections for the 5th time...I traced it to the connection inside the Driver's Side Taillight. There is a big plug-in for alot of the wires. Your fuel pump wiring goes right though it. Well, with the taillight out, it started. Re-install the taillight is stalled and died.
Turns out the connection has a little bit of a bind on the wiring once connected and then stuffed into the body cavity. We "picked" the wires out that related to the fuel pump (pink and black if I remember right) and cleaned them and "pinched the end so it would plug in "tighter".
I have not had a single problem with it since.
I believe the connection, after years of being plugged in and somewhat of a "bind", it slowly allowed moisture and stress to corrode the inside terminals.
I'm not sure this will fix your application, but I certainly check it.