With high fuel pressure, the first thing that pops into my head is some sort of obstruction in the fuel filter, fuel lines or fuel rail, or possibly a kinked line.
When's the last time the filter was changed?
Inspect the entire fuel path (lines/rail) for kinks/bends.
If you can get your hands on a cut-off return line with fuel rail quick-connect, you could hook that to your return on the fuel rail, put the other end into a fuel can, and check pressure then; if it's normal, at least you know the obstruction is somewhere after the rail.
