aldedemon - my FPR part number is 000 078 18 89.
richard28 - I am not familiar with duty cycle reading, need to define what you mean ( I am only amature mechanic on weekends). From what I read FPR keeps the LH injectors running at 38 psi fuel pressure and when there is vaccum from the intake maifold, due to opening of throttle plate there would be vacuum and that would increase the FPR pressure to 45 psi to increase fuel delivery (FPR has a vaccum connection to the maifold). All these are too fast for (lambda) Oxygen sensor to monitor and micromange the operation of the LH inection. I would guess in my case that the FPR when it got hot from the normal engine operating temperature was not maintaining 38 psi or increasing to 45 when there was demand and that is why it was missing and hesitating. It makes sense, I was getting very good gas milage when it was missing due to fuel starvation.