[WOW! A new glitch to enjoy on this site! I “edited” and “changed” the last line of my previous post. The changed text WILL NOT show on my post!]. The last line should read:
Compare the voltage measured (12 volts expected), on the rear O2 sensor yellow/red wire, to the voltage (12 volts, expected, again) on the yellow/red wire going to the front O2 sensor. They should be the same 12 volts.