Service engine soon light
Old subject which seems to be a constant problem with Z3
1999 Z3 2.5 Liter. Peake code reader E3 & E4 O2 sensor adaptation limit cyl 1-3 & 4-6
Have changed, CCV Valve and hoses, O2 pre cat sensors, fuel filter, done a leak test on hoses, no leaks evident.
Could it be the fuel tank emissions, charcoal canisiter, vent lines?
Any suggestions what to check next?