What’s going on guys just picked up another third gen! 07 5.9 mega cab 4wd fully loaded marine has 250k bought it from a family member who did meticulous maintenance at a well know diesel shop in there area. Well being as the mileage is about Tim injectors wear out and I don’t know if they have been replaced I searched for tests to do. I’m not getting any white smoke or lope even after the truck sat for 4 months literally 0 smoke. Also I’m not gaining oil level. But when I free rev the truck in idle the rpm sticks for 2-3 secs then drops down. I’ve been getting a ton of mixed information reading forums from people saying it’s programmed into the computer to do that and others guaranteed that that’s bad injectors. I’m just trying to prevent myself from sticking an injector and melting a cylinder as this truck has 0 blowby not even a haze TIA!