Crazy high fuel pressure (50-60lb) on '02 3L

[lorenambrose]

OK, thanks for expanding on that. So pressure at the test point should be steady ~60 psi regardless of vacuum or engine load - I'll try rigging up my pressure gauge and take it for a drive.

Does the ECM see manifold vacuum on these returnless systems via a MAP sensor or similar?

The ECM does not see vacuum directly. Vacuum is an indication of load on the engine but the ECM figures this out mathimatically via the sensor inputs and displays the data as %load. ~60 psi is right for fuel pressure. 47-63 is the proper range for the flex fuel V6. The fuel system is a little odd. On my truck I get about 40 psi with key on engine off, but 60 psi with the engine running.