In 1986 I bought a 1982 CJ7 that was traded in at the dealership I was working at. We used to run the sand in Mexico a lot back then and horsepower came in really handy. In the earl 90s sometime I installed a TPI 350 and a turbo 350, solved the running in sand issue quite well. It used to set idle a lot and in the early 2000s it started to become very sluggish and was running hotter. Took it to a friend who owned an independent shop told him the symptoms and added it was like the cat was plugged. He suggested an injector flush and with no improvement he wanted to replace the injectors. That motor had 9 injectors and @ $200 each I said pass. Took it to another shop, told him about the symptoms, said it was like a plugged cat, they took the cat out and it ran great. So they do come apart inside and get plugged. I had to put on a new one, they check in AZ during emissions. Sorry about the length.