Computer Issues, Check Engine

[98SteedaGT]

Put on the 80mm Pro-M MAF from Steeda. Check Engine light comes on now after a couple of days... The computer readings indicate that the rear two 02 sensors aren't sending data to the ECM. What gives? I know the 02 sensors are ok, as I can put the factory MAF back on and the light never comes on. This MAF is calibrated for my car, I have already spoke with Steeda and Pro-Flow about the S/N on it. Calibration is 96GT19STK for my 98 GT-19lbs/hr-and Natural Aspirated Car. Read sig to see specs on car along with Steeda TA (14deg) and Under Drive Pulleys. Also, I would like to add that while on the Diagnostic Computer at a friends shop, the Engine Codes clear themselves out and it will be ok again, so we think all is fine. A few days later, the light will come back on and it will read too lean from rear 02, then go back off. I have a customer chip in the car, but I am thinking maybe I need to have it reburned or just send my whol ECM off and have it recalibrated for all the new stuff. I have already tried MIL just incase that was causing issues, since I have hi-flow cats. They didn't do anything other than waste 60.00 and 20min install time. I can clear the computer and run for 2-3 days just fine, then it just comes on again. I run 93 octane, and I don't even drive it that hard (at least right now, until I get this resolved). I have tried normal break in times for the computer and components, as well as hard running a few times to let it learn WOT. No one seems to know what to do.. A local shop wants to replace the rear 02 sensors, but I don't see how that will fix the issue as I can put the factory MAF on and fix the light. I am not sending this piece back, as it set me back money.... Need some options please.