[Damien]

Most computer controlled circuits are given constant power and grounded by the ecu. That way the ecu has less of a load on it and makes less heat.

You said it is getting fuel, but did you check the pressure? A plugged filter or weak pump will cause driveability problems like you described. If I change a fuel filter on a truck I think could have a bad pump, I make sure I have the truck somewhere I can change the pump. I have had TBI trucks run ok, then change the fuel filter and not start again. The fuel pump will loose its prime when the filter is removed and is too weak start it again. On a TBI truck, there is not a schrader valve to connect a gauge, so either you get a fitting with a valve to connect inline at the throttle body or a T fitting that goes in place of the fuel filter.

Also check all of your grounds and electrical connectors for corrosion, starting with the battery cables. Check the connector on the fuel tank too.

I would try to stick with the TBI. It is a great system for a DD.