P0300 on a 2017 Ford F 150 Crew Cab

P0300 is a generic OBD2 powertrain code for random or multiple cylinder misfire. Unlike P0301 through P0308, it does not point to one specific cylinder, so the cause can be ignition, fuel, air, sensor, or mechanical.

Not your vehicle? See general P0300 info.

Most common causes on the 2017 Ford F 150 Crew Cab

Ranked from 1,066 NHTSA owner complaints filed for this vehicle.

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1
Cam phaser (VCT) failure / worn timing chain
High severity
By far the dominant pattern in this batch: 5.0L cold-start rattle traced to worn Variable Camshaft Timing (VCT) cam phasers and timing chain slop (Ford Customer Satisfaction Program 21N03 / TSB 23-2143), which throws valve timing off enough to cause a rough-running, multi-cylinder misfire.
Reported in 21 NHTSA complaints
Parts:cam phaser timing chain timing chain guide VCT solenoid
2
Intake manifold runner control failure
Medium severity
Two complaints describe a known intake manifold runner control fault (stuck runner, SES code, LIMP mode) on this truck series that causes poor performance and can register as a misfire.
Reported in 2 NHTSA complaints
Parts:intake manifold
3
Head gasket failure / coolant intrusion
High severity
One complaint documents a cracked cylinder head gasket diagnosed by the dealer, consistent with a low-compression cylinder that misfires.
Reported in 1 NHTSA complaint
Parts:cylinder head gasket
4
Worn or fouled spark plugs
Low severity
Extended service intervals or a plug nearing end-of-life produce a weak spark and intermittent misfire, especially under load.
Common cause
Parts:spark plug
5
Failing ignition coil(s)
Medium severity
A coil breaking down under heat/load misfires a specific cylinder, most commonly at higher RPM or towing load.
Common cause
Parts:ignition coil
6
Clogged or leaking fuel injector
Medium severity
A partially clogged or dribbling injector under- or over-fuels a cylinder, producing an intermittent misfire.
Common cause
Parts:fuel injector
7
Vacuum leak
Low severity
Unmetered air entering the intake leans out one or more cylinders enough to misfire, particularly at idle.
Common cause
8
Carbon-fouled intake valves (direct injection)
Low severity
Direct-injected engines like the EcoBoost/Coyote don't get fuel washing the valves, so carbon buildup can disrupt airflow/sealing and contribute to misfire over time.
Common cause

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These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0300 on your car still needs shop confirmation before any repair.

Common symptoms

Flashing or steady check engine light
Rough idle
Shaking under acceleration
Loss of power
Fuel smell from exhaust

What to check before replacing parts

Scan for cylinder-specific misfire codes

Look for: A companion P0301–P0308 pins the misfire to one cylinder — start there. P0300 with no cylinder code points at something hitting several at once: fuel pressure, a large vacuum leak, or timing.

Inspect the spark plugs and coils

Look for: Pull the plugs: black/sooty = rich, oily = oil intrusion, white/blistered = lean or overheating, cracked porcelain or an out-of-spec gap = replace. Then swap a coil to another cylinder — if a cylinder-specific code follows the coil, the coil is bad.

Check fuel trims for a vacuum leak

Look for: High positive short- and long-term trims (worst at idle, improving as RPM rises) mean unmetered air is getting in. Smoke-test the intake and listen for hissing.

Verify fuel pressure

Look for: Compare running/cranking pressure to the vehicle spec. Low or dropping pressure starves multiple cylinders and reads as a random misfire — suspect the pump, filter, or regulator.

Compression / leak-down test if ignition and fuel check out

Look for: A cylinder 15%+ below the others, or leak-down hissing from the intake (intake valve), exhaust (exhaust valve), or oil filler (rings), means the misfire is mechanical — not a swap-in part.

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Matching symptoms

Car Runs Rough Flashing Check Engine Light