P0300 on a 2016 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 2016 Ford F 150 Super Crew

Ranked from 1,686 NHTSA owner complaints filed for this vehicle.

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1
Cam phaser / VCT solenoid / timing chain wear (5.0L and EcoBoost engines)
High severity
Widely reported forum/TSB issue on this generation of F-150 — worn cam phasers, VCT solenoids, and timing chain guides cause a rattle on startup, fluctuating idle RPM, stalling, and stuttering; replacing plugs/coils alone doesn't fix it, but new phasers, phaser filters, and VCT solenoids do.
Reported in 6 NHTSA complaints
Parts:cam phaser VCT solenoid timing chain timing chain tensioner
2
Worn cylinder-head valve guides (Ford TSB 19-2384)
High severity
A documented Ford defect on these engines — worn valve guides cause a persistent misfire that reappears even after coil replacement; dealer diagnosis typically calls for a new cylinder head or long block.
Reported in 1 NHTSA complaint
Parts:cylinder head
3
Carbon buildup on intake valves/pistons (direct-injection EcoBoost)
High severity
Direct injection leaves no fuel to wash the intake valves, letting carbon accumulate; in this fleet it progressed to cracked pistons and turbo/valve failure, so don't ignore rough running with high carbon load on a boroscope check.
Reported in 1 NHTSA complaint
4
Coolant intrusion into a cylinder cracking the head
High severity
Reported on this truck as white exhaust smoke on startup with rough idle, diagnosed as coolant entering a cylinder and cracking the head; a cooling-system pressure test and cylinder leak-down test confirm it.
Reported in 1 NHTSA complaint
Parts:cylinder head head gasket
5
Worn or fouled spark plugs
Low severity
Standard misfire cause — worn, gapped, or fouled plugs fail to consistently ignite the mixture; inspect for wear or incorrect gap.
Common cause
Parts:spark plug
6
Failing ignition coil(s)
Medium severity
A weak coil-on-plug unit causes an isolated or migrating misfire, often worse hot or under load; swap-test coils between cylinders to confirm.
Common cause
Parts:ignition coil
7
Clogged or leaking fuel injector(s)
Medium severity
A restricted or dripping injector unbalances that cylinder's air-fuel mixture; injector balance/flow testing confirms it.
Common cause
Parts:fuel injector
8
Vacuum or intake leak
Medium severity
Unmetered air leans out one or more cylinders enough to misfire, especially at idle; smoke-test intake boots and vacuum lines.
Common cause
9
EGR valve or passage fault
Low severity
A stuck-open EGR valve over-dilutes the intake charge, causing a lean misfire at idle/light load; check EGR flow and passages for carbon clogging.
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