i have a 1024kb pcm from a yukon controlling my 6.0l 2bar turbo regal. i have my ve dialed in within a percent or 2 and my injector data, i feel is good. car performs awesome and responds fine in open loop. i notice when i put it in closed loop that my wideband reads a percent or so rich . so first i had it setup at 14.2 for e10 and thought i had a tank of unadulterated gas and set it to 14.7 ....no difference. i did some reading and i have a pretty good understanding of how closed loop mode vs. airflow relates to switchpoints. i lowered my points in the concerned area to 350mv then everywhere and .....no difference. i would like to get lean idle and psuedo lean cruise as well as a proper reading wideband all while using the fuel trims but it seems like it ain't happening . i know i can just get what i want in open loop but i would like the pcm to control my trimming if i could. so.....

am i missing something?
is my pcm hard coded?(has an ethanol table that was flat)

any insight would be appreciated.