It kinda sounds like you're guessing about the presence and location of leaks. Before throwing clamps at it, I'd recommend using a clear hose to see if you even have air. Start at the line entering the I.P.
If you see air there, then move backwards until you find the likely source.
In my limited experience, the primer pump itself is the likely culprit, although it is weird at only 35k. I've also seen cracked hard lines along the frame.
Your issue, if it is indeed air in the lines, could be anywhere from the pickup in the tank forward.
If you end up replacing lines or doing other maintenance leading to a lot of empty plumbing, you might find it useful to disconnect the the line going to the I.P. and use the primer to fill everything with fuel, and then execute the procedure I described above.
The 1hz is also really good at firing up with small amounts of air in the line by self-priming/bleeding. I have dual tanks and have accidentally run one dry, coasted to the side of the road, switched to aux, and primed/bled from the driver seat by just cranking the engine for 15s a couple times. Often you don't even have to crack the injectors.
