Jeff, that's a good point, worth more than the standard going rate for opinions.
The other side of the coin is the value of learning something. Frankly, after a lifetime in technology pursuits, I'm still thrilled to combine book knowledge with practical experience. I was delighted to watch for the first time the meter response to passing the sensor through the parts of the gas flame and understand its electrochemical battery action, not much concerned with the rate of progress making cheap home repairs.

But, I also recognize many around me who could care less. They just want it fixed reliably. The practical side of that, given the difficulty in replacement of the lambda sond is get a new one. Play with the old one to convince yourself it really needed replacement!

Kindest regards, and pardon me for injecting opinion into the tech forum.
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Art Benstein near Baltimore Crrrrazy Ray's!