Please help! Run out of ideas for strange loss of power (1 Viewer)

[gummycarbs]

Away for a few days but will carry on investigating when back - how would I go about monitoring the fuel pressure on an OBD1 truck?

The FSM shows the correct way. You have to thread an adapter into the fuel rail at the very back. It's a PITA. You can tap in earlier, like at the fuel filter, but that won't verify that your fuel pressure regulator is working correctly.