The first LWB I purchased has similar symptoms that I haven't been able to fix. After replacing the ECU, fuel pump, filter, timing belt, coil, FI rails and injectors, TPS, IAC, and other long forgotten things...truck is played with once every 6 months, runs for about 3 heartbeats at 400 rpm, then stalls and doesn't restart.

Sorry this isn't helpful, but commiserating none-the-less.

Russell

1987 Raider - Roxy
1988 Mighty Max 2.6L Turbo - Pearl
1997 Mountaineer V8 - Freddy
2000 Excursion V10 - Freya