'92 300SE

Just replaced the fuel filter. New plugs, cap, rotor (obscene amout of $ for the previous two parts), wires.

Car runs like it's short on fuel at higher revs, like when attempting to pass at speed. Starts to "run out of steam" at about 4,500-5,000rpm. I would think the motor would pull strongly to at least 6,000 given it's redline of 6,500+.

Seems like a fuel issue - no misfire as far as I can tell, and when you back out of the throttle and let it shift, you feel the acceleration increase.

Could this be fuel-pump related? I know there are two, maybe one is on its last legs?

Any ideas?