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Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 23001
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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Need some help on a diagnosis we are trying to figure out at

Customer Question

Need some help on a diagnosis we are trying to figure out at our shop. Got a 2002 Ford F250 Super Duty 6.8 v10 pickup and it came in with a code p0305 in the system (cylinder #5 misfire detected).
After diagnosing- spark plugs and ignition coils and injectors are good. Compression is good. Performed a leakdown test; has 40% leakage past ring but has leakage past on intake valve (can hear it).
Note: cylinder head was replaced about 13,000 miles ago.
Submitted: 1 month ago.
Category: Ford
Expert:  john -aka eauto replied 1 month ago.

have you pulled the valve cover?

Customer: replied 1 month ago.
No, not yet. We will do that first thing Monday morning since our guys are gone for the weekend.
Expert:  john -aka eauto replied 1 month ago.

sounds like a burnt valve any carbon build up