1. just got a 1993 300 E 2.8 the car has a surge in the idle, code said replaced o2 sensor also the code called out MAF Sensor. However after replacing the O2 Sensor the wiring harness shorted out while pluging in the MFA sensor. I replaced engine wiring harness. Did not fix check the Actuator wiring bad replaced same codes. Took to dealer could not fix. Replace the computer the surge is gone however I have an fault code of 42. Help