Got my answer quickly via pmail from both Mike Collum and Eric Zeno.

Thanks to both.

It is the same thread for the Digijet  / 1.9l WBX O2 sensor or oxygen
sensor, 18 x 1.5.  (Using both phrases here and in reply title for
future archive searchers.)

Eric also noted that this is the same as many spark plugs which I had
seen in the archives, but importantly he pointed out something I didn't
know  - that you can get a spark plug thread tool in many FLAPS.

No need to go get an expensive tap and die tool or tool set to fix this
thread.

Sam

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Sam Walters

Baltimore, MD