2009 Mini Cooper Clubman, non-turbo, manual

I have one code left to solve, 2B56 - Mass Air Volume Flow 'A' Too Low The ECU is still seeing too small of inlet volume of air passing the MAF. I am at a loss of what to look at next other than wiring to the Mass Airflow Sensor. Below is a list of the current issues with the car:

• Low power / poor acceleration. Max speed is ~65 mph.
• Engine cuts out at RPM above 3000k like one cylinder stops firing for a moment. Car bucks when it does this. Keep it below 60 MPH in in top gear and it runs smooth but with no guts.

Things that have been done to this car to date. When I bought the car it barely ran and did not idle well.

• Replaced plugs, idles better, no codes fixed
• Changed oil and air filter (always do this with any car)
• Filled up with fresh 90 octane gas, no changes
• Foxwell scanner showed that the throttle was not opening all the way or at the speed the pedal was being pressed. Replaced throttle body, this helped the car to respond greatly. Removed throttle codes
• Cleaned Vanos sensors. Helped idle
• Replaced Mass Air Flow Sensor. Idles well now, code still exist for Mass air flow sensor
• Replaced Differential Pressure Sensor on intake, Removed codes for this
• Verified that the o2 sensors where in spec
• Replaced water temp sensor, fan was staying on longer than I expected it to. This fixed that issue
• Checked for misfires with scanner. Before the above fixes there were several on all cylinders. Now there are none at idle. When revving the engine there are intermittent ones here and there at a vary low rate on different cylinders. For this reason I do not suspect the coils as it is across the board but not consistent.

 

I would start by checking for vacuum leaks, particularly on the rubber boot connecting the MAF to the TB.