If you haven't tried adding this to your oil at oil changes, I'd highly recommend you do so before you let anyone work on the engine. 230k miles isn't very many for a 7.3 that hasn't been abused. Has the engine ever had a air intake problem where you sucked dust into the engine? https://powerstrokehelp.com/ Bill is full of hot air but knows his stuff about powerstroke engines, and his how to videos are excellent. I'd fix the truck and run it till you can't fix it.
https://www.walmart.com/ip/Hot-Shot...r-Diesel-Oil-Additive-32-FL-OZ/182440933
https://www.archoil.com/products/ar9100-oil-additive

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