I have a 350 TPI engine where I am trying to tune my own prom with the $6E mask.

I set the closed loop enable temp to max so that i could drive it around and set MAF tables in open loop.

drove for a little while with no problems and adjusting the tables to get VERY close to 14.7 as I could. then I noticed whenever driving under very light throttle, or starting from a stop the wideband would max out lean and the engine would basically turn off for a moment then come back.

We were using the moates ostrich 2.0 but noticed the same problem when burning an actual prom and using that instead.

We did some datalogging and I looked at everything I can think of and all sensor outputs seemed reasonable however i did notice that the target afr would shoot up to fully lean for a split second wherever the stutters occured.

when I played with DFCO and tried to turn it off by maxing out all values to the extreme, it made the problem WAY worse (just in case this helps).

What could be causing this spike in target AFR and how would I go about fixing it?

any pointers / possibilities would be appreciated, the car drives great but this issue happens so much it is almost undrivable.

I have attached a short datalog session where the spike happens a few times in a short period if it helps.

Thank you.