I just got back from the Big Bend Open Road Race.

About 11 miles out from the finish, the AFR's spiked lean (22:1+ = lost fuel pressure to the rails). I pulled my foot out, got back in, did it again, pulled back out, waited a few seconds, and all was well when I got back in it. That happened every mile or so to the finish line. I had no other issues for the entire race (please note the second leg finish is straight and you're in the gas the entire time, while the first leg finish is not the same regarding throttle towards the finish line - there are a few corners that keep you from keeping your foot in it constant).

As far as I can tell, I still had about 6 gallons in the factory tank when this occurred.

My fuel system is as such:
-Factory style 1/2" pickup with fuel sock
-Carter 4600HP (100 gph low pressure). 1/2" in, 3/8" out.
-BC Bronco's 1 quart fuel accumulator (diesel fuel filter with pickup reaching to bottom of filter)
-Walbro GSL392 (mounted angled about even with the filter/accumulator)
-Wix 33737 corvette regulator/filter (under passenger seat)
-return line from regulator back to T above the BC Bronco's accumulator back to tank

I've had the lean spike happen before, on a road course, with very low fuel (sub 2-3 gallons) and a looong sweeper. Since then, I plan my fuel usage to never go below about 4-5 gallons on the road course and I haven't had a problem since.

Also, I had my original Walbro GSL392 fail on Wednesday of last week after the practice rounds and 60 mile drive back to the hotel. Ordered one overnight from summit, put it in, and that's what I ran the race with. I assumed it failed at 3,200 miles because I've ran it out of fuel once and had the issue on a road course with sweepers a few times.

I'm going to pull the filter/accumulator and see what I see. I'll also pull the pickup and get an idea as to if the sock is okay, etc. At this point, I'm curious if the root cause of my first pump failure and my losing fuel pressure at the end of the race may be related.

Possibilities:
-130 mph sustained causing fuel slosh that didn't allow the carter to keep up with walbro demand
-Dead-head system from under passenger seat to fuel rails causing issues
-'return' line into a T above the BC Bronco's fuel filter/accumulator may not actually allow much returned fuel from the corvette regulator into the accumulator

Anybody have any thoughts on this?

Also, I wasn't thrilled that the GSL392 failed at 3200 miles. How reliable is that pump (if I never run it dry)?

Here's a little diagram of my fuel system (diagram made by someone else).