The airmass meter, is it a known 100% good bosch one? (including the one you swapped with?).
If the air mass readings are correct, then the ecu seems to be behaving, (could well be wrong!! ).
I still having a nagging suspicion it's not drawing enough air due to a mechanical fault .
You have poor maf flow, & corresponding poor map readings, (most likely due to the ecu injecting less due to it thinking it's poor flow).
What happens when you floor it on the road? what are your map readings & airflow then? what happens if you disconnect the maf & floor it? & the readings?
don't let it get you down............the answer is somewhere, it's just finding it!