Put the year and model in your signature along with that a... phase.

Okay, now on to emission analysis. Your emission control system is working as well as it can as indicated by the zero percent O2. As with most Mercs of this era, the HC is above average for the year group. Many are at the ragged edge of the limit. Also, FWIW, the NOx is commendably low.

The numbers for a 400E probably don't get much better than what yours achieved.

Duke