1. It sounds like you have a bad BMW Technician working on your car. Having said that, it should NOT be your responsibility. Just saying. Too often they read codes and replace parts, and do not understand the underlying issues.

2. You MUST get a list of ever code that is thrown. The dealer is most likely documenting part of what they find and doing so in a way that protects BMW. Lemon laws require the same fault/problem to happen (say) 3 times...but if the paperwork has different issues listed, you will not be able to prove it. "The CEL came on" is NOT THE FAILURE. 3 cels is not a lemon.

3. Did you have the intake are temp sensor recall done?