So this is a bit of a spitball as there is not a lot to go on here. Assuming you have checked for codes with an OBDII tool and/or a more advanced tool just to see if there are any clues and you found nothing, then this is my take.
If there are no clues and it was my truck, knowing what I know about the FPCM issue and for under $65 and the ease to replace it, I would get a new FPCM, swap it in and see what happens. It may or may not resolve the problem, but here are some things to consider:
1. I have not had a chance to dig down and see what a more advance scan tool can see with regard to the low pressure fuel system. I doubt the FPCM had the smarts to indicate an intermittent fault and I am not sure there is a low pressure fuel sensor.
2. The FPCM are known problems, they often hard fail, however, I have seen instances where they fail intermittently. A bad solder joint that over heats or is subject to issue with low ambient temperature would not likely be easy to find and could cause the problem you are having.
3. Even if the FPCM is not your problem, there are 2 good outcomes here:
a. You have eliminated the FPCM as a problem so you and or the dealer/repair shop can focus on other areas if the problem persists.
b. You then have a spare, backup, FPCM for when the operational one actually fails and leaves you stranded.
c. You can always sell the spare FPCM module and recoup most or all of your money if you choose not to keep a spare in the truck.
d. If the replacement FPCM solves your problem and it would have been a warranty repair, then you could submit for reimbursement for the part and/or labor if you had a shop swap the module. Effectively you are out nothing in this instance,
See this link here for more info on the FPCM part number and some sources -
https://www.tahoeyukonforum.com/threads/spare-fpcm-fuel-pump-control-module-wise-idea.152090/
While you may be covered under warranty, for the $65 or less the FPCM costs and the easy of replacement, to me it is not worth even dropping such an intermittent problem off at the dealer for repair as they likely will not duplicate the problem and you will be having the same problem and discussion months from now. Changing just 1 variable that is somewhat of a known problem would be a great way to eliminate the FCPM or possibly solve your problem.
Good luck.
