93 240 nonTurbo, non-California

I replaced the O2 sensor 10 months ago with a Walker 3 wire universal. I soldered the wires vice using the crimp connectors they supplied. No issues until last week. 2-1-2 code. Good voltage readings from the sensor wire, about .57 volts and appropriate fluctuations when I created vacuum leaks or made throttle adjustments. Wire to the ECU has good continuity. Good +12V to the heating element. After idling for 10 minutes, the resistance reading in the heating element didn't change, always about 7 ohms. Not the 13 ohms hot or 3 ohms cold. So I think I've got a bad heating function in the sensor. Cleared the code. Drove it for about 4 days. Yesterday after a 2-3 minute trip. Turned the car off, returned in about 10 minutes, started the car as normal and there that check engine light is again... 2-1-2.

So, here are my choices, and I'm open to other ideas. It is still under warranty:

1. Replace it with another Walker 3 wire universal and solder it again. Warranty replacement.
2. Buy the direct fit plugin by Walker. $105 less $50 warranty credit
3. Buy the direct fit plugin by Bosch. $119 less $50 warranty credit

The motor is in great condition. I'm leaning towards buying the direct plug in because I don't want to jack around with the soldering again. I'm also leaning towards the Bosch because the one in there now is the Walker universal.

Thanks for listening/reading!