Change it. Do a 2x 'drain-fill-. Change all the rubber bits and bridges too.


It may die in 10k. If you do the fluid change you will declare "it was doing the change that screwed me" if you DONT, you will declare "a fluid change might have saved it"


You are doing a gentle drain/fill...and NOT a "flush". Dont associate issues that can come up with an aggressive power flush with a simple fluid change.


Also. O2s are a maintenance item. For a reason. Wonder what that has been doing to your motor? AFRs? Fuel dilation? hydrocarbon loads in the Cats....who knows....