How do you diagnose a bad injector on a 6.7 PowerStroke? This 2015 F-350 came in with 197,000 miles—still on the original injectors. The owner broke down over the weekend, hearing a loud engine knock. Our tech, Jaime, ran a cylinder contribution test—disabling injectors one by one. Sure enough, turning off the suspected injector made the knock disappear, confirming it’s overfueling. ✔ Checked for excessive crankcase pressure—no signs of a cracked piston. ✔ Ran a relative compression test—all cyl