460 Ford RV

[Zoom45]

My 1988 Ford E350 Holiday Rambler recently had a surging feel with the cruise on under a load. It ran pretty good other than that. I decided to change the fuel filter. About 13 months ago I installed a new Airtex sender and pump in the tank. I did a pressure test on the frame mounted pump and it met all the pressure requirements. When I changed the filter this time the rear in tank pump would not run to prime the new filter. I finally ran a jumper wire from the plug on the firewall and grounded it at the rear under the tank so I could hear if the pump was running. It wasn't but I could hear the high pressure pump on the frame running. While the jumper was hooked up I bumped the bottom of the tank hard and the in tank pump started running. The filter primed and the engine ran great. Could this problem just be a bad ground to the rear tank or should I go ahead and install another new pump. Either the ground is bad or the pump was sticking.
Thanks,
Zoom45

[Nick-B]

Smacking the tank to get the in-tank pump running is typical of a failing pump.
Airtex pumps are cheap for a reason and known for short lifespans.
A Motorcraft replacement is the best, albeit more expensive replacement.