BMW Repair: engine light and runability problems, airflow sensor, air path

Question
i replaced the computer in my 540 after being told by the dealer i needed to along with the spark plugs intake and valve cover gaskets and im still having the same problem car runs really bad and whenever i hook my scanner to it it gives me a different code how can i approach this prob on a 2000 540 bmw

Answer
Too many options to diagnosis on line, but here's your next steps.

In spite of your e39 being a high performance piece of work, it's still the basics.  You need air, fuel, and spark.

Check that you are getting fuel to each cylinder. Check if each cylinder is getting spark.  I'll assume your air path is clear, but you may have a bad airflow sensor.

Sorry.