For those of you who have been following our Project Box Hauler series, you’ll remember our high-miler, ’01 Ford F-350 dually with 200,000-plus miles on it, was diagnosed with a couple of dead cylinders, more specifically No. 3 and No. 8. Upon his initial diagnosis, Nate Brekken at Strictly Diesel in Scottsdale, Ariz., guessed the problem would more than likely be bad injectors on those cylinders since injectors get fairly tired and worn out on the 7.3s after about 150,000 miles. On the other hand, two dead holes could mean more serious issues, such as bad valves or poor compression from worn-out piston rings, or even a cracked cylinder head.