my c180 kompressor merc failed its national car test emissions test. I'll have to get rid of it if I can't fix it. The results are this.
Low idle: engine oil temperature 106C
(780 rpm). CO 2.12vol%. Above 0.30% FAIL
HC 88ppm


High Idle. Lambda 0.93
(2.940 rpm). CO 2.69 vol%
HC 87 ppm.

My merc has 209000km on the clock and is driving quite well, would be a shame to have to get rid of it. My mechanic says it could be a host of various things and fixing one thing might not get it past the NCT (test).
Any person have an idea how to rectify same.

The lambda has to be between 0.97 and 1.03