Funny fuel pump failure mode....

[gggdds]

Had just had my car (76' 911s, 110Kmiles...)into Precision Motion for an oil change and valve adjustment...had some problems with it apparently running lean...kind of a miss at <2000 rpm when hot...I had disconnected the electrical to the warm up regulator, and it seemed to help, but it was getting worse...and...apparently intermittent...Don had the car for the day, checking the fuel accumulator and fuel pressures (he wasn't happy with how long it took for the pressure to come up....) and delivered it to me (apparently running fine!!) where I work for my trip home...when I started it, it seemed to miss at lower rpms...a lot...and back fired as I accelerated across intersections--very embarrassing!....I live in the mountains, and the trip up the mountain was miserable, having to keep the rpm's close to 4000 to keep the car rolling....I called Don, and suggested, "...could it be a fuel pump?" and he said yes. I've been carrying one around in the trunk since 2008 (rebuilt from PartsHeaven) and this pm, I installed it...all symptoms gone...car seems perfect...I took the old pump apart, and it looked fine--but I can't tell what worn rollers look like in the rotary pump section...the motor part is fine....I'm hoping this was the problem, and I'll drive the car here on the mountain before taking it down again....Ideas?