My guess is your ammeter is off. Its off 2ma at KOEO and when it should be zero it is 3-4 different. Looks very similar to me.

The fact you are in closed loop means you really are set-up in a way that should be plenty clean enough for IM testing. I would guess the catalyst is either degraded or too cool in the recent test.

I'm not in a testing area so I'm not too knowledgable on testing technique but I have read of products that perk up cats for testing purposes. I also would recommend a decarbonizing treatment and a good hard highway drive before the next test. On the day of the test also drive the car hard 3rd gear all the way, maybe.

And fix the EHA, and put in a new set of plugs.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician