1988 Ford Other

Engine Performance problem
1988 Other Ford Models V8 Two Wheel Drive Manual 31,000 miles

Please provide specs for fuel pressure for a Ford E 350 motorhome with a 7.5 liter engine. We are only showing 35- 40 psi and this seems to be low for a high presssure pump. We have no power uphills and seems to be dumping gas as it only got 3 mpg as we nursed it home. We installed new plugs, wires, cap, rotor, map sensor, and O2 sensor. Cat conv. Ok. Have not pulled exhaust yet as pressure seems strong and unit is welded. Vacuum pressure seems to be weak. Any suggestions much appreciated.
July 30, 2008.

460/7.5L engine

The fuel pressure is within specification 30-45psi

Vacuum pressure seems to be weak: If you're refering this as vacuum better check the exhaust for excessive backpressure-either a pressure or vacuum gauge will do-

EXHAUST SYSTEM BLOCKAGE: high reading when engine first started, falling back to 1 or zero and gradually increasing to 15 or 17.

Good Luck

Jul 30, 2008.