If the catalytic converter didn't like it, it would throw a code I'd think....sure there may be some "lee way" - it may not throw the code right away...for example...
But from what I understand, TCW-3 is the "poor man's Marvel Mystery Oil"
lubes the fuel system (rail, injectors, pump, etc...), some say it causes the gasoline to "burn hotter" making it actually better at cleaning; particularly cleaning the exhaust....
I've been a big fan of MMO
But may have to give this a shot. Only "caveat" I can see if the awkward size of the bottles lol. MMO's bottles aren't too bad.....but all the TCW-3 bottles are either big jugs, quarts, or awkwardly shaped to get "just that right" angle to pour it clean into the tank
If I've done my research right, the most common ratio seems to be 1 oz. TCW-3 to 5 oz. of gasoline, or 2 oz. TCW-3 to 10 gallons of gasoline.....there are some people claiming "mixing" MMO and TCW-3....but that's a little "too much" IMHO
Oh yea, and just make sure it's a TCW-3 rated additive!
Looking at WM, I found they have a couple different "2 cycle oils" - 3 or so bottles in the auto section alone. A "soft sided" squeeze bottle called "Precise Mix" that I believe is 12 oz...., a "2 Cycle Oil" bottle that is in a 4 oz. bottle, and then they have a 16 oz. bottle (I think...) that is labeled "TCW-3" - that's the one you want.
and then if you go over to the lawn and garden, they got a whole conglomerate over there to choose from too.
They even got a neat little "shorty" Sta-Bil bottle, I believe it was even 4 oz. about the perfect size to hold TCW-3 in a baggie in the trunk lol.