LML P0087 + water in fuel

[JoeCap]

Hey there, new to this forum, I've run up against a few problems with my LML. 2011 2500HD with 105k miles, it is all stock, no mods or tunes. I find similar issues posted with older models but the fuel system/emissions changes to LML are not accounted for so I am hoping I can find some help here. Truck seems to run great the little I have driven it due to Corona registering it is a problem, so some illegal driving has been my only testing.
I did a full service on the truck when I bought it, which I hoped would solve the check engine light, and replaced the FPR with the Exergy one, seemed like cheap insurance, no metal from the CP4. I cleared the codes then after running it a bit I will get a water in fuel warning(new filter, drained it-no water), next the Filter life goes from 100% to 0%. lastly within 10 miles the P0087 low fuel pressure code pops back on.
I did disconnect the water sensor, but still get the filter life dropping to 0% as soon as I give it some throttle.
What should be my next move to solve this?

[DmaxMaverick]

Welcome aboard!

Water (or whatever) in the fuel can cause both issues. You may have a problem with something other than just fuel and/or water in the tank. Pull a sample from the water drain into a clear glass container and let it stand undisturbed for a couple hours. Any real water in it will separate from fuel, and any dark color may indicate a biological (algae). A large amount of gasoline can cause a similar condition. If enough gas is in it to cause serious running issues, you should be able to smell it.

[JoeCap]

Thanks for the response. So I drained the filter and no separation. The tank was close to empty and filled with clean diesel. Still having the same issue.
What should be my next step in trouble shooting this?

[Kennedy]

Q: Are you running a black plastic Napa/Wix fuel filter?

[richp]

Hi,

FWIW, John Kennedy's lift pump and a mild computer adjustment totally cured my LMM's 0087 problems.

Something to add to your thinking if other efforts don't pan out.

[JoeCap]

Running a Racor filter. Had a GM filter which looked the same before it.