My (all original cats) California emissions truck nearly 10 years older than your 94 Ross had two cats but now has only one ~ we removed the front cat coz it was totally plugged crystalized like solid stone ~ no replacements are available & the only way exhaust passed thru was that canister style cat was surrounded by a 1/4" thick metal mesh screen (see my cat cyl head thread photos) Well anyway IMHO I think an engine can run better on an ECM if it gets accurate data from O2 sensors ~ so if the ECM is tuning your engine THEN I if me would inspect test repair replace as needed the cat & O2 sensor/s

We are so blessed to own our little truck ~ although maintenance $ has cost a good penny ~ it is finally running pretty decent, not burning oil and gets 20.5+ MPG with off road AT tires ~ it's paid off too ~ we need it for medical appointments in Honolulu & grocery runs to the MCBH 4 miles from our apt ~ God Bless America

And Best Wishes to you too Ross