Ok, I bought a DMM with duty cycle measurement. I connect the positive to pin#3 of the diagnostic X11 terminal, and negative to ground. I read a duty cycle that oscillates between 29%-35% at idle. The article in DIY states a slightly rich mixture at 35%, hence I assume I am running rich.
Here is the catch, in another website: [URL=http://pages.prodigy.net/jforgione/MB_Lmbda.html], the graph states a LEAN mixture to anything on the right hand of the graph (below 50%).
Am I lean or rich?
I have attached the graph for illustration.

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