High dwell reading, again

[2-3 heaven]

I was going to post this in my 83 Flathood Questions post, but figured we kind of got off topic on there anyway.

1983 242T with stock B21FT. The car is barely accelerating until the revs build a little. Then it runs fine. Starts okay and cruises okay. Rechecked my dwell and it's back to 87. Unhooked the O2 sensor and it drops down to 45. Tried warrantying the O2, but the new one does the same thing. As soon as it is hooked up, the dwell increases to 87 like I'm grounding the circuit. I tried doing a lean test with a 1.5V battery, and the reading dropped to 10. That would make me believe the computer and wiring are okay. Is it at all likely that I had an O2 go out in a month, about 2k miles, and the replacement was faulty? Any other suggestions? You can hear the frequency valve changing pitch also, so I don't think that is part of it.