Agree that you should get codes read and make educated decisions, however, these problems cause more that just the 2 lean codes you listed.
But also from looking at a lot of these cars lately, all e46 are of the age and mileage the the 3 items I listed are VERY common, easy to inspected for and cheap and easy to replace. A few screw drivers and a small socket set is all that is needed to DIY the items I have listed.
This is not like dealing with VANOS O-rings or complete CCV replacement.
Just wanted to put out there the simple and common causes before tackeling the harder and more expensive issues. The assumption is also basic maintenance has been kept up like spark plugs, fuel filter, air filter and so on.
Unfortunately I keep finding owners expecting the more difficult problems and overlooking and/or discounting the simple issues.