Believe it or Not
Some 2011-2013 Ford F-Super Duty vehicles equipped with the 6.7L diesel engine may exhibit a runs rough/misfire condition only during the exhaust regeneration process. This condition typically occurs on light throttle tip-in between 40-70 mph and will not set a DTC. The concern may be intermittent and a knocking noise may be present during the concern.
If the customer indicates that the message center displayed a Cleaning Exhaust Filter message prior to the concern, using IDS or equivalent, retrieve DTCs from the PCM.
If no DTCs are found, remove the left side cylinder head and replace all eight exhaust valves and valve seals. Refer to the workshop manual section 303-01.