Having almost the same issues. My issue is with 8FGCU25 model. But months back the lift just died and would only start after it cooled down. Shortly after it just wouldn't start. So I changed the regulator, and the solenoid and the fuel filter assembly (not new parts as I used the parts from a downed lift soon to be scrapped. After changing parts I got almost 40 hours out of it before it stopped running again. Lift will start with starter fluid! Checked the regulator which is good to my knowledge after testing it with the big hose off and not getting any pressure when cranking. I did check to see if I was getting power to the solenoid which it wasn't so I am going to check the relay
(Signal Generator) that was mentioned above.