Verify that the rubber isolator in the fuel rod ball-joint on the firewall hasn't split. Happened to me. I wondered why flooring it barely let me drive 30 mph. Thought I was running out of fuel.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans