Lean at first accel, like a bad accel pump on a holley

Norman C Shibley

25 year ASE master tech
Have this over in normal tech section as well. 80# injectors, fresh from a FullThrottle cleaning, a TT6.1 chip... GN seems like it has a carb with a bad Accel pump. Going from a normal cruise which seems lean enough anyways, its going even more lean when you first accelerate. MAF seems fine, TPS is linear, the O2 is new, tried changing the primary FP in the DP set up, tried a different ecm, drained what I thought might be old gas out and filled with fresh gas, fuel pressure rises 1:1 as it should. Nothing has made any difference. I emailed Eric a small file, we'll see what he suggests, but anyone else have any ideas?
I have been chasing the same issue for a year. Except mine also periodically leans out while cruising in addition to off idle accel and i watch the wideband go to sometimes 18/1. Did you ever find anything on your end? New PCM, O2, MAF