93 240+t sputtering when giving it throttle

My 93 +t that I'm wrapping up is having an issue where at lower rpms, if I give it gas it will start to sputter, feels like I'm hitting a fuel dump/ cut. This happens more in the higher gears at lower rpm when I push the throttle quickly. If I slowly roll onto the gas then it will pull hard but start to get very rich as I use more throttle (Wideband starts to read as low as 8.5). I am using a 13c at stock 7psi. Im using the 350cc white top injectors. I replaced the 02 sensor but it made no difference, also tried 3 different MAFs, no difference. What else could be causing this?

One thing that could be making a difference is that the narrowband 02 sensor giving signal to the ecu is all the way down in the cat instead of right after the turbo exit. Not sure if that would make a difference?

Move your narrowband within 8-12 inches after the turbo, also make sure your fuel filter isn?t clogged if you think you?re not getting enough fuel

Also which spark plugs are you using and what are they gapped at and how old are they?

Are you still running your stock fpr and maf or did you switch to ones from a turbo car? Have you chipped or swapped your ecu?

check for collapsing of pre turbo piping

I would check to make sure your intake piping isn't collapsing, for sure. Then I would check fuel pressure. Kinda sounds like it's not getting enough fuel...in tank pump not working/filter sock clogged up...fuel filter could be full of crud...etc...

fixed the sputtering issue by changing my spark plug gap from 0.037 to 0.028 on all plugs. Still runs rich asf past 4k rpm. AFRs get down to 8.5 and it looses power.

Probably sucking the intake hose to the turbo shut. Make sure to check that the crankshaft pulley isn't slipping.