Demolition_Dye

2014 Silverado 4.3L with 131k on the dash. Bought it around oct 2016 with 45k. Left it bone stock up until about 5k ago. The only maintenance that I have done is oil changes really, around 70k had 2 injectors go the dealer blamed it on (bad gas) but they don’t know shit considering they can’t tighten a jam nut during alignment lol Js and about 15 miles after the injector fix I got an engine light and they said it was a bad cat. So I never got It fixed still runs fine. About 5k ago got a intune i3 turner on a whim, and made my own intake, and it woke up big time. also put a 2inch lvl kit on. No catch can but I just got one and will be putting it on soon. Came across this thread while on the hunt for fluids to replace and other maintenance I should do? All suggestions are welcome my ears are open