1999 Ford Ranger XLT 2x4, AOD, 4.0 L engine, 107K miles. VIN X engine code.

This truck has 65 PSI fuel pressure, it's not a flex fuel engine. Some books indicate the fuel pressure should be about 35 PSI some indicate 58/72 +/-

The scanner is showing left and right bank rich and continues to trip the engine lamp. I replaced the fuel pressure regulator. Ford calls it a fuel dampner. Try to find this part number (F87E-9F775 CB) the fuel pressure is still 65 PSI

All part listings for the fuel pressure regulators are incorrect.

Can you give me some direction?

Chuck