W204 C300 MULTIPLE CYLINDER MISSFIRE. MOBILE MECHANIC DIAGNOSES IT.

IF YOU HAVE A W204 C CLASS WITH A 272 ENGINE (INFORMATION CAN BE USED IN OTHER MODELS ALSO) MAKE SURE YOUR O2 SENSOR IS WORKING, THIS VEHICLE HAD NO O2 SENSOR FAULTS BUT THE O2 SENSOR UPSTREAM OF CATALYTIC CONVERTER ON DRIVER SIDE WAS NOT ACTIVATING CAUSING CYL 4,5,6 MISSFIRES.