Jaguar Repair: oxygen sensor continued, nox levels, co hc

Question
This is Eddie again asking about the NOx levels..
The HC reads 92
and the CO reads 0.25

Answer
Your CO and HC are ok as HC limit is about 220 and the CO limit is 1.2 so my guess is you have a over heated combustion chamber as I listed.
Are both your CATs in tact and not gutted? Although I never heard of the CATs affecting NOX much.

If your engine temp is ok and timing ok, you need to find a local shop with test equipment to confirm the testing station.

An over heated CAT might burn the Nitrogen in the air (NOX) but your HC and CO do not indicate any reason to cause a CAT to over heat. It takes a lot of raw fuel in a CAT to get that hot and it would show up as very high HC or CO. HC is generally raw fuel due to an electrical or mechanical problem and CO is fuel mixture.

Howard