About two months ago, I changing head gasket, and everything associated with, including a new O2 sensor, plugs, wires, rotor, dis. cap, fuel filter, water pump, flame trap, hoses, heater control valve, and completed valve job. The car runs great, only a bit low at idle. However, I am getting the check engine light.

After checking codes @ point 2, I get 2-3-1, and 2-3-2. Today, on socket 6, codes 1-4-3 (knock sensor), came on. It was replaced about March 2005.

I have cleared it, but it came back after only 24 miles. I know its calling for o2 sensor adjustment. But this is a brand new Bosch direct fit sensor, and I am totally confused why it is coming on.

BTW, the FI's, intake, and exhaust systems were thourouhly cleaned, as the throttle body.

The person buying the car, isn't concerned, but I am. I don't want them to run into any issues that I couldn't take care of.

Thanks,

Kevin
1990 740GL Rex 215K