This car is a Corvette '97 with following mods:
LS6 cam
Ported heads
LS6 intake
LT headers, no cats
#42 injectors
Blackwing CAI
I tuned it first by STFT+LTFT and checked with PLX WB and I got the VE what I wanted. I did this by disabling MAF (MAF fail Hz=1). So the car works fine with MAF disabled.
When I try to dial in MAF, I get horrible percentage errors thorough the scale both down and up. If I tune it according to %-correction, the next tune may show the same errors in opposite direction. When I sweep through the rpm range in one gear and use the last values per cell, the errors are minimal but in normal driving it still runs rich or lean especially if the pedal is pushed appr. half way.
I already replaced the MAF with another used unit but still exactly the same behaviour.
I enclose here the tune and logs with and without MAF.