Hi everyone, I apologize if this is in the wrong place(still sorta new to the forum). Here's my problem

A few weeks ago I was driving for a good hour or so with everything running "well" on my rebuild, with about 550ish miles so far, when out of nowhere, it seemed like my fuel became too rich out of nowhere. I was already running rich to start with, but it changed to if I have more than like a quarter pedal throttle, the car lags like crazy and, with enough throttle, will back fire a lot. I got my codes checked, and ended up having to change my map sensor, which didn't solve anything. I changed my plugs, and it seemed to work better for about a minute, and then went back to the same problem. The last plugs were all fouled, which didn't surprise me too much, but I'm just confused of why this just happened randomly, without changing any settings on my MS.
After this started I tried messing with the fuel a little, but I'm super afraid of messing up the engine, so I didn't change much besides the fuel pressure at idle mostly.
Could this just be a tuning issue? Maybe a sensor or a connection went bad on the MS wires? Should I just turn down the fuel pressure on my afpr?

Here's my setup:
97 talon, 2.0L 420a, Wiseco pistons, Eagle rods
Wally 255 pump, accel 490cc injectors, 1:1 afpr
manley valve springs and valves
Hahn S16g turbo (no boost as of now for break in), HKS ssqv BOV
MS2extra with mostly default settings until I find a tuner.

thanks in advance for any help!