[brcidd]

An amperage pull check and fuel pressure check are in order- You may have low pressure due to bad electrical connection- as in a bad body ground, or body to engine block ground. See if fuel pressure is low, and if so see if fuel pump pulls at least 6-8 amps or so-

I have had your exact issue- and as I was pumping out tank with questionable fuel pump "jumpered" to continuous 12v, to change fuel pump, I noticed rear tail lights were "dim"- without the light switch on-- seems the tail lights ground through the same body ground as the fuel pump- and the pump was seeking a return ground through the tail light bulbs. The problem was solved by finding the frame to body to battery ground, near engine, was rotted through.

The amp check led me to this- it was only pulling about 4 amps...