Jeff, my thoughts are some debris may be blocking flow in the fixtures insides. You may have to disassemble the fixture. I don't know which fixture your rig has but my OEM fixture was a real pain to take apart.
Once I got into the guts of the thing I found a rubber flow reducer that was clogged. I cut the reducer so that I was still able to keep it in place as designed but to eliminate it's capacity to reduce flow.
After 5 years, I finally replaced it because it was starting to look bad and had some corrosion. Replaced with residential quality.
Pictures attached show the rubber piece and where it's located in my old fixture. By the way, no manual or instructions were included for the OEM fixture.