Mercedes 560sel fuel injection problem
 

Since I've installed the current fuel distributor on my car, my injectors are pulsing rather than spraying continually. When I test them running the fuel pump and pressing down on the air plate, they begin spraying fine, but then at about 10% plate travel they begin to pulse, and continue to pulse faster and faster as I press it further down. The spray pattern only looks continuous after maybe 70% air plate travel. I've replaced the injectors and the fuel filter, with very little difference. My guess is either a fuel pump going bad, or the accumulator, or the pressure regulator, or the fuel distributor itself, thinking the fuel distributor most likely thanks for any help