P0301 is the code your PCM stores when it counts misfire events on cylinder 1 specifically. That is genuinely good news compared with P0300 — the truck has already narrowed the fault to one cylinder for you. On the 5.0L V8, cylinder 1 sits at the front of Bank 1, the passenger-side bank. What the code still does not tell you is which part in that cylinder gave up. Across F-150 model years, a failed ignition coil or a worn spark plug account for the large majority of P0301 repairs, and you can separate those two for free in about fifteen minutes before spending anything.
Match the symptom
Select the closest observation. The result changes the first test; it does not name a part to replace.
Classic single-cylinder misfire behaviour. At idle there is no load to mask the missing contribution, so you feel it most sitting still. Pull freeze-frame data before you touch anything — it records the rpm, load and coolant temperature where the misfire actually happened, and that context is gone the moment you clear the code.
How to confirm the P0301 repair actually held
Clear the code only after you have fixed something specific, and only after the original freeze frame is written down. Clearing first destroys the one record you have of the conditions the misfire happened under, which is exactly what you need to reproduce for verification.
Drive the truck through the rpm, load and coolant-temperature window your freeze frame recorded, and watch the cylinder 1 misfire counter while you do it. Zero counts across the conditions that previously set the code is the proof you want. A dashboard that simply stays dark is not the same thing, particularly for a fault that only appeared under load or when cold.
If the counter starts climbing again, resist the temptation to clear and re-drive. Save the new data instead. A misfire that returns under a different load or temperature than before is telling you something useful about which system is actually failing, and that information disappears every time you reset the memory.
What can set P0301—and how to separate it
The order below is evidence-driven, not a universal probability ranking. Vehicle year, repair history, companion codes and the operating condition in freeze frame change where diagnosis should begin.
| Possible cause | Evidence that supports it | First useful test |
|---|---|---|
| Failing coil-on-plug (most common) | Misfire follows the coil when you move it to another cylinder; boot shows carbon tracking or the connector lock is broken | Swap the cylinder 1 coil with a neighbouring cylinder, clear codes, and see whether the misfire follows the coil |
| Worn, fouled or wrong-gap spark plug | Cylinder 1 plug looks different from the other seven — eroded electrode, cracked insulator, fuel or oil fouling, gap out of specification | Pull the cylinder 1 plug and lay it beside the rest; compare against the year-specific Motorcraft part number and gap |
| Injector fault on cylinder 1 | Misfire stays on cylinder 1 after a coil and plug swap; injector is noticeably quiet, or its electrical resistance is out of line with the others | Listen with a stethoscope, compare injector resistance across cylinders, then run the injector test your scan tool supports |
| Vacuum leak feeding that runner | Bank 1 fuel trims run positive as well as the misfire; a hiss changes with a smoke test near the intake or a broken PCV fitting | Smoke-test the intake and inspect the PCV connections — never spray flammable cleaner at a hot running engine |
| Low compression or a mechanical fault | Misfire will not move with parts; relative compression on cylinder 1 is down, or you hear valvetrain noise from that corner | Run relative compression from the scan tool first, then a mechanical compression or leak-down test if it looks low |
The coil swap: the most valuable free test you can run
Before you buy anything, move the cylinder 1 coil to another cylinder and move that cylinder's coil to position 1. Clear the code, then drive the conditions your freeze frame recorded. What happens next answers the question that would otherwise cost you money.
If the code comes back as P0302 or whichever cylinder now holds the original coil, the coil is faulty and you have proven it without spending a cent. If it comes back as P0301 again, the coil is fine and you have eliminated the single most common cause for free. Either result is worth more than a guess, and this is why every competent diagnostic sequence for a cylinder-specific misfire starts here.
One caution: label the coils before you move them. It is embarrassingly easy to lose track of which coil started where, and then the test tells you nothing.
What the spark plug tells you when you pull it
- Light tan or grey insulator — the plug has been running correctly; look elsewhere for the fault
- Black and sooty — running rich on that cylinder, which points at an injector or a fuel-control problem
- Wet with fuel — that cylinder is not igniting at all, consistent with a dead coil or an injector stuck open
- Oily deposits — oil is entering the combustion chamber, which is a valve-seal or ring problem rather than an ignition one
- Cracked porcelain insulator — replace it; a hairline crack lets spark escape to ground and produces exactly this code
- Gap noticeably wider than the others — normal wear, and on a high-mileage truck often the whole answer
Why replacing all eight coils is the expensive mistake
P0301 has already done the diagnostic work that P0300 leaves you to do. It named the cylinder. Replacing all eight coils on that information throws away the one advantage the code gave you, multiplies the parts bill by eight, and disturbs seven connectors that were working perfectly.
There is a second cost that is easy to miss. If the real fault is an injector or low compression on cylinder 1, eight new coils will not fix it — and now you have spent the diagnostic budget and still have the original misfire. Shops see this sequence constantly: parts first, diagnosis second, and the diagnosis eventually happens anyway.
Save these scan-data clues
Freeze frame is a snapshot of conditions when the PCM matured the fault. It can distinguish an idle-only problem from a load, cold-start or monitor-completion problem. Clearing first throws that context away.
- Engine rpm and calculated load when the misfire counted — idle-only and load-only faults point in different directions
- Engine coolant temperature, which separates a cold-start fault from a fully warm one
- Short and long-term fuel trim on Bank 1; positive trims alongside the misfire suggest air or fuel rather than ignition
- Misfire counters for all eight cylinders, so you can confirm cylinder 1 really is dominating rather than merely leading
- Vehicle speed and throttle position, which tell you whether it happens under acceleration or at steady cruise
- Any companion codes stored at the same moment — P0171, P0316 or a cam/crank code changes the order you work in
A practical diagnostic workflow
- 01Save the evidence before you clear anything
Record the freeze frame and the misfire counters for every cylinder. Once you clear the code that information is gone, and you will have no way to prove your repair worked other than waiting to see whether the light returns.
- 02Confirm cylinder 1 is genuinely dominating
Compare the counters across all eight cylinders. If cylinders 1 and 5 are both climbing, you are looking at something bank-level rather than one failed part. If only cylinder 1 counts, the fault is physically in that cylinder and the search area is now very small.
- 03Inspect the plug before you buy a coil
Cylinder 1 is the front cylinder on the passenger side and one of the more accessible plugs on this engine. Compare it directly against the others — a plug that looks different from its neighbours has usually already told you the answer, and the read-out from its deposits narrows the cause further.
- 04Move the coil, not your money
Swap the cylinder 1 coil with a neighbour, label both, clear the code and drive the conditions from your freeze frame. If the misfire moves, the coil is the fault. If it stays on cylinder 1, you have just ruled out the most common cause for free.
- 05Check the coil boot and connector while it is out
Carbon tracking inside the boot looks like a thin black line running down the insulator, and it lets spark escape to ground. A broken connector lock lets the coil work loose over time. Both are cheap fixes that get missed when someone only inspects the coil body.
- 06Test the injector on that cylinder
With the plug and coil eliminated, listen to the injector and compare its resistance with the rest. Many scan tools can also cut individual injectors and show the resulting rpm drop, which tells you whether that cylinder was contributing at all.
- 07Check compression when parts do not move the fault
A misfire that refuses to follow any component is a mechanical one. Relative compression from the scan tool is quick and non-invasive; follow it with a proper compression or leak-down test if the numbers look wrong. This is the point at which the job stops being a DIY afternoon.
- 08Verify with data, not with the dash light
After the repair, drive the load and temperature conditions the freeze frame recorded and watch the misfire counters stay at zero. A lamp that stays off for five minutes at idle proves nothing about a misfire that only appeared under load.
Do not replace all eight coils and all eight plugs because one cylinder misfired. P0301 has already done the hard part and named the cylinder. Blanket replacement costs eight times as much, risks damaging seven healthy connectors, and — if the real fault is compression or an injector — leaves you exactly where you started with an empty wallet. Do the free coil swap first. It takes fifteen minutes and it either finds the fault or eliminates the most likely one.
Ford service bulletins that name P0301
A bulletin does not automatically apply to your truck. Check the exact model year, engine and build date it covers, and have a dealer or shop confirm whether your VIN is included before paying for the work it describes.
| Bulletin | Applies to | What it says |
|---|---|---|
| TSB 20-2324 | Some 2018 F-150 with 2.7L EcoBoost (supersedes 18-2310) | Illuminated MIL with P2196, P2198, P0300, P0301, P0306, P0316, P0171 and/or P0174 stored. Ford attributes the condition to PCM software or direct-injection fuel injectors leaking down, and the service procedure covers PCM reprogramming and/or injector replacement. |
P0301 repair cost comparison
These are planning ranges gathered from public U.S. estimate data, not quotations. Your figure moves with local labour rates, model year, engine and whether the shop bills diagnosis separately. Use them to judge whether a quote is reasonable — not to decide what is wrong.
| Repair | Parts only | Shop total | DIY difficulty | Notes |
|---|---|---|---|---|
| Coil swap diagnostic test | $0 | Usually inside a diagnostic fee | Easy — 15 minutes, basic hand tools | Identifies or eliminates the most common cause before you spend anything |
| Single ignition coil replacement | About $40–$100 | Roughly $150–$300 per coil | Easy on the 5.0L — coil is on top of the plug | Labour is typically under an hour; parts are widely available |
| Spark plug (single cylinder) | About $15–$25 | Often bundled with coil labour | Easy for cylinder 1; harder for rear cylinders | Many owners replace the boot at the same time |
| Full set of eight plugs | About $120–$200 | Varies widely by model year and access | Moderate — rear cylinders are tight | Sensible as maintenance at interval; not a diagnosis for P0301 |
| Fuel injector (single) | Varies by engine and year | Get a quote — direct-injection parts cost more | Advanced on direct-injection engines | Only after coil and plug are eliminated by testing |
| Typical all-in P0301 repair | — | Commonly $100–$500 | — | Wide range because the cause ranges from a $20 plug to internal engine work |
Why the model year changes the test
The F-150 5.0L badge covers several Coyote generations. Use the VIN, calibration and underhood emissions label when selecting service information or parts.
- Cylinder 1 is the front cylinder on Bank 1, the passenger-side bank on the 5.0L V8. Do not carry a bank convention over from another manufacturer, because it will send you to the wrong side of the engine.
- Spark-plug part numbers and gap specifications changed across 5.0L generations. Look yours up by VIN rather than trusting a parts-counter cross-reference, and note that some model years use a plug that is not intended to be re-gapped.
- On 2.7L EcoBoost trucks, Ford has linked P0301 alongside other misfire and fuel-trim codes to leaking direct-injection fuel injectors and PCM calibration. If your truck is a 2.7L rather than a 5.0L, check whether a bulletin covers your VIN before buying ignition parts.
- Later trucks store more detailed misfire data than early ones. If your scan tool shows only a code and no counters, borrow one that reads live misfire data before you start replacing parts.
P0301 FAQ
Where is cylinder 1 on a Ford F-150 5.0L?+
At the front of Bank 1, which is the passenger-side bank. That makes it one of the more accessible cylinders on this engine, so plug and coil inspection is usually straightforward compared with the rear cylinders.
Can I drive with P0301?+
Only briefly and gently, and only if the light is steady rather than flashing. A flashing light means the misfire is actively threatening your catalytic converters, and you should stop as soon as it is safe to do so.
How much does it cost to fix P0301 on an F-150?+
Most repairs land somewhere between $100 and $500 all-in. A coil is commonly $150–$300 fitted, and a single spark plug can be under $50. The range is wide because the same code can mean a $20 plug or internal engine work.
Should I replace the coil or the plug first?+
Inspect the plug first, because it costs nothing and it frequently shows the fault outright. Then move the coil to a different cylinder — if the misfire follows it, you have identified the coil without buying anything at all.
What is the difference between P0301 and P0300?+
P0301 names cylinder 1 specifically. P0300 means the PCM saw misfire across several cylinders, or with no single cylinder dominating. P0301 is much easier to chase because the diagnosis starts in one known place.
Why did P0301 come back after I replaced the plug and coil?+
Because the fault was never in the ignition system. A misfire that survives new plugs and coils is usually an injector or a compression problem, and both are diagnosed by testing rather than by buying more parts.
Can a vacuum leak cause a single-cylinder misfire?+
Yes, if the leak feeds one intake runner or one injector seal. The tell is positive Bank 1 fuel trims alongside the misfire. A smoke test finds it quickly and safely.
Is P0301 covered by any Ford service bulletin?+
On 2018 F-150 trucks with the 2.7L EcoBoost, Ford TSB 20-2324 lists P0301 among several codes linked to PCM software and leaking direct-injection injectors. It does not apply to the 5.0L, and a bulletin only applies if your VIN falls inside its coverage.
Ford diagnostic references
These documents explain Ford monitor operation. Exact pinpoint tests, connector views and specifications must be selected for the truck's VIN and model year in current service information.
01Ford 2017 gasoline OBD operation summaryFord EVAP, misfire, fuel and comprehensive-component monitor descriptions↗02Ford 2024–2025 gasoline OBD operation summaryFord monitor logic, enabling conditions and drive-cycle requirements↗03P0301 on 2019–2025 Ford F-150: causes and fixesModel-year-specific cause ranking and part-cost reference for cylinder 1 misfire↗04NHTSA technical service bulletin searchPublic database for confirming whether a bulletin covers your VIN and model year↗05Ford owner manuals and warranty guidesOfficial year- and VIN-specific manual lookup for your vehicle↗