Hmm...
@TYM4FUN, I am indeed confused by which thing, in particular, you are correcting.
Above you said:
"The post 02 IS suppose to have a near flat line close to zero volts. This means it is working..."
Voltage seemed to be the main point you were making?
But, if everything were working, this would indicate an average lean condition. Average stochiometric mixture is what it wants to see, which is around sensor mid scale, so very roughly 0.3V to 0.5V, not near zero.
Stuck near zero will probably earn you some kind of error code, or maybe just lack of the cat readyness code.
"By the catalysts converting the gases, there will no longer be a fluctuation in rich/lean cycling. If the rear 02 is showing a wave form like the front sensor, it is an indication of bad catalytic converters."
Agree completely here, except that, as an old age allowance, you can have an old degraded cat, not quite dead yet, with a pretty active downstream waveform. They seem to allow considerable leeway for that.
I brought back an expensive OEM mandrel bent stainless steel tube / dual cat metallic core header system from the dead (P0430) to passing, by doing the hot citric/oxalic acid de-scaling treatment. Downstream waveforms before treatment were identical to upstream, indicating good working downstream sensors, but dead cat. After treatment (P0430 went away) were still banging full scale, but paused about 20% in the mid-scale region, and it was OK with that.
Not sure what implication about waveforms you might be referring to, but, I generically call any waveform a waveform, even flat ones.
Requires more descriptive words to get specific.
