I installed the big line kit and a fuel pressure guage. Everything was working fine, but now my fuel pressure guage bobbles back and forth when the truck is running and will stay in the area that the pressure should be. When I shut the truck off it doesnt bobble and slowly drops (wired it on a switch). Could this mean something is wrong with the pump, guage, or what? Any ideas?

Ok... Did you use a isolator, snubber or a needle valve? (Need one of the listed for either electric or mechanical gauge).As for the pump you wired on a switch? This not a good idea there is several that have done this too and you'll; tend to forget to turn on the pump when your in a hurry. Also starting proessure might be to high and cause starting troubles.

Tell ya the truth, couldn't tell ya. I simply used/did everything the intructions told me to. The guage I have is the ISSPRO EV2 electric. It didnt start doing till after I wired the up the backlighting.

Even though its a electric sender its going to get beat up from the pulses of the VP44 and lift pump this why I suggest putting a needle valve or a snubber on even electric gauges. But since the problem came after the back lighting I would back up and disconnect it and see if the problem still there. Basically double check your wiring... Grounds are really important!