Hey all,
I have a 2004 Mini Cooper s. It does have a 15 reduction pulley it also has a Alta cai and custom exhaust also tuned. Bought it this way.
I recently thru a mil light no biggie I scanned it I get two codes ones p0234 over boost ok not a big deal. The other code I have no clue where to start I’m getting a p0171 system too lean bank one. Car drives fine most of the time does occasionally stall when at a light. Anywhere to start looking to fix this would be great. Thanks!

 

You might have a vacuum leak. Look at the small hoses. I had the one under the fuel pressure regulator come off before.

the rubber gets soft and won’t stay on.

 

I will once I get home ! I’m at work at the moment thank you tho your the only one to reply so far 😁

 

Might want to consider your oxygen sensors also.