bad fpr or bad pump

[Warped]

A while back I made about a dozen runs down the 1/8 mile. Dialed in carefully with the DS. Checked the first 6 runs and everything was fine. On about the 8th run the O2's started to drop severely beginning at about 3800 in each gear. Got progressively worse with each run. On the last run it started at 820 and dropped to 740. At the 1-2 shift picked back up to about 800 then dropped to 700. Picked back back up to only 750 on the 2-3 shift. Walbro, adj fpr set to 45, and new fuel filter. Are there any specific symptoms that would differentiate a bad pump from a bad regulator?

 

[WarpSpeed]

It would be helpful to have a fuel psi gauge to watch during a run/test run to help determine the problem. It could be pump, regulator, filter, kinked fuel line, leaking vac hose to the regulator, etc. . Sounds like it happened pretty fast to be a regulator or pump, but you can't be sure. I had a reg. go out once,,, it let fuel psi go up to @ 55psi normally, but than it just stayed there(Turned out the seat washed out.)