XSeries-forum

Here are the current codes the 05...m54 B 30 is facing with 225k on the clock...
P0 174
P0 171
P0 442

What scanner are you using?

Those codes look like generic P-codes rather than BMW codes.

P0174 comes back as “mixture too lean, Bank 2”. As you only have a 6-cyl engine, you don’t have a ‘Bank 2’ as that’s a V8 thing.

P0171 is ‘mixture too lean’. It might be right for a 6-cyl. Points at an issue with the mixture control but doesn’t give any more than that.

P0442 is a ‘leak in the evaporative emission control’ - stops petrol fumes escaping.

If you can get hold of a tool (borrow) that gives the BMW error codes, that will help narrow things down a bit. I use Carly but that’s a paid for product and you have to use their Bluetooth/wifi dongle. You may find someone local with the kit.

Running too lean is sometimes a leak in the rubber trunking between the airflow meter and the inlet manifold , its reporting the lambda is out of range of adjustment due to too much unmetered air getting in so there is probably an airleak somewhere .
The evap system could just be the "gas" cap isn't sealing anymore .