I would try putting the factory intake tube (between MAF and throttle body) back on. Compare to service recommendations below when this code occurs on factory vehicles.
The engine control module (ECM) detects that the actual measured air flow from the MAF, MAP, and throttle position sensors is not within range of the calculated air flow that is derived from the system of models for greater than 2 s.
Verify the integrity of the entire air induction system by verifying that none of the conditions listed below exist:
Any damaged components
Improperly installed components
Collapsed, restricted, or damaged components
Loose clamps, cracks, or other damage
An air flow restriction
Restricted air filter
Splits, kinks, leaks, or improper connections at the vacuum hoses
Vacuum leaks at the intake manifold, MAP sensor, and throttle body
Water intrusion
Any snow or ice buildup, in cold climates
Contamination of the multifunction intake air sensor element
If you find no mechanical issues, I think a competent tuner should be able to resolve the problem.