Swapping parts on a WAG is just foolish! Test the pump first, and only change it if it needs to be changed. Vapor lock on anything newer than a 1953 Ford flathead V-8 with the pump mounted high over the intake manifold is highly unlikely, due to the way newer fuel pumps are positioned in relation to the tank. Lifting gas a foot or more above tank level with the suction side of the pump was what caused vapor lock, as the fuel vaporized under high vacuum conditions, and it's hard to pump enough vapor to make an engine run. The early Cadillac OHV V-8's also put the pump above the intake manifold, just like the Fords, and they vapor locked, too.
Run a pressure and volume test, and if you find a bad pump, replace it. Otherwise, find the fuel system restriction if it's starving, or fix the flooding condition if it's loading up. Like Sun Electric Co. used to say, "We test- - - - -not guess!"
Jerry
