2020–2025 Ford 6.8L/7.3L Engine Tick With a Misfire? Test the Layers in Order

Tick Plus Misfire: Which Layer?

An upper-engine tick and a cylinder-misfire code on a Ford 6.8L or 7.3L gasoline engine sound like one expensive verdict. They are not. Treat them as two observations that may converge only after the ignition layer has been cleared. Save the complete scan, freeze frame, misfire counters, and a cold-versus-hot recording before moving a part.

If a plug becomes a justified suspect, an off-engine comparative spark-plug tester can help determine whether several removed plugs behave alike under the same bench setting. The AUTOOL SPT360 spark plug tester is one way to make that comparison. It cannot load a plug at cylinder pressure, prove a coil or wire fault, identify valvetrain noise, find metal in the oil filter, or authorize engine disassembly.

Ford TSB 25-2572 supplies the useful order: locate the contributing cylinder, test the serviceable ignition pieces, and exit the bulletin if the fault follows one of them. Only a misfire that stays with the cylinder earns the deeper oil-filter and valvetrain branch.

Name the two complaints separately

Write one line for the sound and another for combustion. For the sound, record cold or hot, idle or load, upper or lower engine, frequency, and whether rpm changes it. For combustion, record P0301 through P0308, current versus history status, power-balance contribution, and the operating conditions in freeze frame.

A phone recording made from fixed locations can help a technician hear change over time, but it is not a stethoscope diagnosis. Injector operation, an exhaust leak, accessory noise, normal mechanical activity, and valvetrain impact can overlap in a recording. Likewise, one P030x code identifies the cylinder whose combustion monitor objected; it does not identify the failed piece.

Stop running the engine if the oil-pressure warning illuminates, the noise becomes a heavy knock, metal is visible, or the engine runs violently. Repeatedly demonstrating a severe misfire can overheat the catalyst.

Check the Ford scope before opening the ladder

The published bulletin covers specific 2020–2025 F-Super Duty, 2021–2025 E-Series and F-650/F-750, and 2020–2025 F-53/F-59 applications with the listed 6.8L or 7.3L gasoline engines. Model year alone is not enough. Confirm VIN, engine, build information, calibrations, prior repairs, and the latest Ford workshop procedure.

That matters because the same code on a different engine may have a different ignition layout, cylinder numbering, known issues, or test sequence. A TSB is technical service guidance, not automatic recall or warranty coverage. Check the VIN separately for open programs and let current service information control the repair.

Locate the weak cylinder without buying a part

Begin with the saved code set, but confirm the active contributor with Ford’s power-balance or relative-contribution method. Watch the event at the same coolant temperature and load that produced the complaint. A cylinder that appears weak only during a cold start tells a different story from one that drops continuously at warm idle.

Before removing anything, inspect the coil connector, plug wire routing where fitted, boot seating, moisture or oil in the well, damaged insulation, and evidence of an earlier repair. Check whether fuel trim, injector command, or voltage moved at the same moment. The goal is to choose one cylinder and one next variable—not to create a pile of eight unlabeled components.

Observation	Next justified layer	What is still unproved
One cylinder repeatedly loses contribution	Inspect and compare its serviceable ignition parts	Which ignition or mechanical part failed
Misfire moves after one controlled swap	Test or replace the component that carried it	That the valvetrain needs work
Misfire stays with the original cylinder	Restore parts, then open fuel/compression/internal branches	That the tick and misfire share one cause
Several cylinders change together	Look for common fuel, voltage, timing, or operating conditions	Eight simultaneous plug failures

Move one ignition variable at a time

Label every removed part by original cylinder. Swap only the plug, wire, or coil named by the current Ford procedure, restore connectors and routing, clear codes only after saving them, and reproduce the same condition. If two parts move at once, a moved misfire cannot identify which one carried the fault.

Inspect plug gap, deposits, cracks, tracking, terminal damage, and whether its appearance differs from its neighbors. A bench comparison is supporting evidence: a plug that behaves poorly beside seven stable plugs deserves attention, but atmospheric bench behavior is easier than firing through compressed mixture. A plug that looks good on the bench can still fail in the engine.

Keep plug torque, engine temperature, high-voltage safety, and thread condition inside the workshop procedure. Do not probe secondary ignition with ordinary meter leads.

Let a moved misfire close the case

This is the most valuable exit on the ladder. If the weak contribution moves to the recipient cylinder after one controlled component move, the component has changed the fault location. Ford’s bulletin says to leave its internal-engine path and repair that ignition cause under normal diagnosis.

Confirm the result by returning a known-good component or installing the approved repair, then repeat the exact temperature and load. Do not continue cutting open an oil filter merely because a tick was also reported. The simplest branch has produced a repeatable cause-and-effect result.

If the fault does not move, put every component back in its documented location before continuing. A stayed misfire is permission to test the next layer, not proof of an internal engine failure.

Open the oil-filter evidence gate

Ford places oil-filter inspection downstream of the ignition checks. That gate protects the engine from unnecessary intrusion while preserving evidence if the misfire remains tied to the cylinder and the upper tick is confirmed.

Oil and filter handling belong with a trained technician who can follow the current procedure, use a proper filter cutter, and distinguish normal material from abnormal metal. Grinding or sawing a filter can manufacture debris. Save photographs, sample location, mileage on the oil, oil level, oil specification, and whether the particles are magnetic. One glittering fleck without controlled collection is not a valvetrain verdict.

No metal does not guarantee every internal part is healthy. Metal, however, raises the stop-work urgency and changes what invasive inspection may be justified.

Keep valvetrain work behind professional boundaries

Only after the misfire stays, the sound is localized, and the bulletin’s evidence gates are satisfied should the covered valvetrain path be considered. Cylinder leakage, compression, borescope findings, oil pressure, and valvetrain movement may be required by current Ford information.

Internal timing and valvetrain work involve heavy components, precise timing, fastener replacement rules, and engine-damage risk. This article does not convert TSB 25-2572 into a driveway repair. Its purpose is to prevent an ignition fault from being carried unnecessarily into that branch and to give the shop a clean record when deeper work is justified.

Repeat the idle and load conditions that started it

Verification needs two columns: sound and combustion. Repeat the original cold or warm idle, then the original safe load. Compare the recording locations, power balance, misfire counters, codes, oil-pressure warnings, and driveability. Re-scan every relevant module after a complete drive cycle.

A repair is supported when the misfire no longer follows or remains on the original cylinder, the tick is absent or identified as a separate normal sound, and no new fault was introduced. Verify both complaints independently; a cleared code after five quiet minutes is not the same result.

Official references

• Ford TSB 25-2572: 6.8L/7.3L upper-engine tick and cylinder-misfire workflow
• Ford VIN recall and field-service-action lookup