Weird Airdog issue
 

Need ideas/help. 2003 5.9 California SO model. AirDog 100.

Weird issue...Over the last week my fuel pressure gauge has been been dropping from it's steady 10-11psi down to zero. It's when it occurs that is weird.

When I accelerate normally, stays steady at 10-11psi. When I let up, it drops to anywhere from 2-7psi. When I really punch it, it can drop down to zero. I've also been getting an error code: Low Voltage to the lift Pump once every day or two.

I've cleaned and put dielectric grease on all the connections. No change.

Put on new fuel filter and water separator. No change.

Took off the square relay and drove w/o it. No difference, so I ordered one on Amazon. Should be in on Monday. Any chance that could cause this?

I took my Smarty back to stock setting. No change.

Finally, I checked all hoses and they look good. Have not done anything to the quick connect fitting on top of the fuel tank. Can that be reconnected if I take it off w/o ruining the fitting?

Seems to be electrical but I don't know what else to check...I can't check voltage when it happens???

Thanks in advance for any ideas! Heading out Tues to Idaho, pulling a 5th wheel, so I'm a little concerned.
__________________
2003 Ram 3500, 2wd, SRW, Quad Cab 5.9L CTD, 5spd, SO, 3.73. ATS Intake Manifold, S&B Cold Air Intake. PAKBRAKE 120db Air horn & exhaust brake. IssPro gauges: (Pyro, Boost, Fuel. Trany, R. Diff) SMARTY SR (awesome)! Prodigy Brake Controller. Air Dog 100. TST tire monitors x 6, FAST tranny cooler, PML Rear Diff Cover, 2009 Montana 3665RE @ 13,500lbs.