I appreciate all the informative replies, thanks!

Duke, the test was done on a dynometer at 2 speeds. The results I posted were at high speed (25mph), and the low speed (15mph) results were virtually the same so I didn't post them.

I will definitely check the EGR valve and tube for proper operation and passage and ask the testing station about the high oxygen readings -- there are NO exhaust leaks so I'm at a loss as to that anomalous reading.

Also of note, the wife had mid-grade fuel in the system at time of test (89 octane).

Again, thanks to all for the replies.

__________________
-Paul-
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi