gastank presher buildup causing problems

All "carbon can" cars should have what is known as a "pressure vacuum" cap. These caps allow SOME vacuum OR pressure to build SAFELY and the caps are then supposed to relieve.

IF you have the proper cap, and IF it isn't all corroded/ rusted "shut," then the pressure did not cause the fuel pump problem.

Stroke is correct, though. The CAP is NOT the primary "vent" but rather the entire properly hooked up and working system.

The problem of course, is, that these cars are so old, that "anything" could have happened, including "mis wired" (hosed?) parts missing, lines crimped/ missing/ rusted shut/ plugged.