These are the pictures of Daves faulty reading HO'2 sensor. This very well may have been the reason he ran the cleaner through it to get it to pass the last smog test. Looking at it I feel it has been going bad for a while after reading this thread and the replacement of the catalytic converter and all of the tune-up parts as well.
This is a prime example that it does'nt matter how well you maintain your vehicle the O'2 sensor can effect the whole running aspects of your vehicle and not turn on a "check engine" light.
This one obviously was sending a signal of too rich "lean me out" for quite some time causing drive-ability problems as well.
With the cost of fuel these days it is a good idea to bench test them, or just replace them as part of your regular tune-ups. Note this only pertains to the front O'2 sensors before the catalytic converter, as the sensors behind the converters only test the converters operation.