50 psi @ WOT not in spec? OK, maybe we're getting somewhere.
What should fuel pressures be on this car? Any idea?

I'll check that return line.

The PO had the regulator changed at the dealer a few years ago because of a hard start issue.

I ended up buying a gauge to monitor the pressure. Kind of funny driving around with it taped to the windshield. You don't realize how raked the windshield of a S40 is until you have to look at something perpendicular to it!

I was surprised at how much the pressure varied. 42 psi when priming the fuel rail (not running, just cycling the key), but only 32+/- at idle, and then the 50 psi. I just expected that it would remain very constant like the 28 psi on a D-jet.

Thanks.