You are running a 12.1 engine on 93 pump ???

I would look at your fuel, what do you have a for a fuel pump , if electric can you here a change in the sound of the pump when this occurs ?

Fuel pressure gauge ???

There could also be an issue with wiring going thru the bulkhead if the wiring is still original and you have the factory ammeter still in play ?


running up my post count some more .