Fuel pressure per the FSM (at least my '85 edition) is supposed to be 27-31 psi at high vacuum (i.e @ idle) and 33-38 psi at 0 vacuum. Might want to check a later model FSM for the pressure on the '93 engine, but I think it is always below 40 psi at the top end.

r.c.brown@ieee.org
TruckEditor@tlca.org
Project: 4Crawler
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