P0300 on a 2020 Ford F 150 Super Crew

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 2020 Ford F 150 Super Crew

Ranked from 506 NHTSA owner complaints filed for this vehicle.

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1
Cam phaser (VCT actuator) failure disrupting valve timing
High severity
Numerous owners had a rattling/knocking cold-start noise diagnosed as failed cam phasers (Ford campaign 21N03) on the 5.0L; incorrect valve timing at idle commonly causes rough running and misfire codes.
Reported in 5 NHTSA complaints
Parts:cam phaser timing chain
2
Low compression from chronic oil consumption / worn rings
High severity
Several owners report the 5.0L burning significant oil, in some cases leading to engine replacement; ring/bore wear lowers compression enough to cause a cylinder to misfire.
Reported in 3 NHTSA complaints
3
Worn or fouled spark plugs
Low severity
Standard high-mileage misfire cause; check for wear, fouling, or incorrect gap.
Common cause
Parts:spark plug
4
Failing ignition coil(s)
Medium severity
A weak or arcing coil-on-plug unit causes a repeatable single- or multi-cylinder misfire; swap-test to isolate.
Common cause
Parts:ignition coil
5
Clogged or leaking fuel injector
Medium severity
An injector delivering too little (clog) or dribbling (leak) fuel unbalances that cylinder's mixture and misfires.
Common cause
Parts:fuel injector
6
Vacuum/intake air leak
Low severity
Unmetered air leaning out one or more cylinders causes an intermittent misfire, often worse at idle.
Common cause
7
Carbon-fouled intake valves
Low severity
Direct-injection engines like the 5.0L accumulate carbon on the backs of the intake valves over time, disrupting airflow/mixture at idle.
Common cause
8
EGR valve stuck open or faulty
Low severity
Excess or mistimed exhaust gas recirculation destabilizes combustion, most noticeable at idle and light throttle.
Common cause
Parts:EGR valve

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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