P0300 on BMW Petrol – Random/Multiple Misfire

BMW turbo petrol notes for P0300. Most often ignition-related, but trims and boost leaks can create load-only misfires.

Common BMW Petrol Causes

  • Tired spark plugs (gap too wide) and weak coils under load.
  • Boost leaks creating lean pockets when boosting.
  • PCV/breather faults causing idle trims to climb.

Suggested Test Plan

  1. Check misfire counters; swap coils to see if misfire follows.
  2. Check trims at idle vs load.
  3. Pressure test charge-air system if misfires are load-only or P0299 exists.