Well 3 days ago i changed the Camshaft Sensor on my 318 (I heard that this was a common problem on 318s and had a code that described cam sensor malfunction) and now is fixed. Then yesterday morning i changed my plugs with BMW NGK's 4+ (the dealer recommended those for my car).
And today i got another code (P0420 = the PCM determined that the catalytic converter is not working proprely).
Does this mean that my Cat is clogged? Could it be because of the new plugs i put on the car? (the plugs are stock) what should i do?