The new left cat was waiting for me when I got home tonight and got installed without incident. I took the car for a 15 minute drive with the sensor plot on. This is attached, and can be compared to the plot in my initial post. The B2S1 "dithers" are now crisper, and B2S2 has stabilized at around .6 volts. Overall, B2 readings are almost identical to B1. So it looks like the problem is resolved. Time will tell.

Also attached, the new MB cat compared to the old "replacement" unit.

Attached Thumbnails

   

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe