Was curious so I have two cats on my 94 ranger and it is a single exhaust not a dual was wondering would it cause the truck problems or fail inspection if I were to take one of the cats off meaning as why do I even need two cats on a single exhaust.

 

Cats can get plugged up if they get old a break up inside, tap on them with rubber mallet or wood to see if you hear rattling, that would be a bad sign

Cats are added to meet emissions for that year in the state they were sold, so it may have needed 2 to meet emissions, so to pass inspections you would need 2, and they do check

Calif has strictest inspections, you also have to use Calif approved Cats, these come with a sticker you must put under the hood so inspector can see its number, if they notice the new cat, no number no pass

To see if you have clogged/blocked exhaust you can use a vacuum gauge, $20, to see if cranking vacuum and running vacuum are what they should be
Cranking 4-5", foot OFF the gas pedal
Running, at any idle, 17-21"

Blocked exhaust would have lower vacuum because air can't be pushed out
You can remove both O2 sensors to give exhaust another exit and if vacuum comes up then exhaust is clogged