Fuel pressure regulator? Very common VX ailment it seems, and a faulty one would be causing the symptoms you've described.
Fuel pressure regulator? Very common VX ailment it seems, and a faulty one would be causing the symptoms you've described.
Is it possible it was just checked during one of those "good" moments though?
And the downloadable manual suggests that "Key On" fuel pressure should be between 333-376 kpa (48-55 psi).
If the problem is intermittent like you described, who knows if even the comparably low pressures you read remain constant under actual load/driving conditions.
My initial search term was "fuel pressure", and when following one of the "fuel pressure regulator" search results, I saw a link that said "fuel system diagnosis". After that I used "fuel system diagnosis" as my search term, and the fuel pressure readings were listed under a few different topics.
Most of the results were in section 6E - Engine\ 6VE1 3.5L Engine Driveability and Emissions.