The test numbers are rather odd. For example, with 1.1 percent O2 at 15 MPH, I'm surprised it passed HC. A properly functioning emission system including the cat should be near zero. High O2 means the cat may not be functioning properly or the mixture is too rich.

It goes extremely rich at 25 MPH indicated by the very high CO. Eventhough the O2 sensor light has never illuminated the O2 duty cycle should be inspected with a scope and it should have a voltage cycling frequency of about 0.5 Hz. If the O2 sensor is functioning properly, then the problem probably lies elsewhere in the "E" part of the KE system.

Search the term "duty cycle". I'm not sure if your model year has that dianostic, but it's used to set the basic mechanical mixture adjustment, and it must be in the proper range for the E part of the system to maintain the proper stiochiometric mixture. If the factory seal has been removed, it's been adjusted, but if the adjustment is done improperly without using the proper procedure, which is common, it can lead to high emissions.

Check that the WOT switch on the throttle body functions properly for both the idle and WOT function.

I don't know your level of knowledge or experience or what equipment you might have, but you may be wise to find an experienced MB Indy, discuss the problems with him and ask what diagnostics he can run to isolate the problem.

Reading my previous posts on KE emission diagnosis should at least give you the background to ask the right questions.

Duke