Yesterday I had a local call me with a 2007 LBZ exhibiting same P0087 symptoms. Had him remove the POS plastic fuel filter and stop by. System restriction good. Pump tested good ramping psi at idle.

I made a couple of tuning changes to allow more RPM and TQ in limp mode (not convinced that this will work) and a single table change to his stock tune and we'll see what happens. Also set him up with a monitor to watch pressure, temp, and rate.

This is a 70k "rebuilder" that is supposed to be legit miles. He hauls with it pretty much daily, but it's not yet at a point where it will act up on demand. Takes the better part of the day and maybe a hot soak to get it to act up. Thankfully it's local so if it persists I can do a ride along and hopefully find a work around.