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P0300

P0300 on a 2016 Ford F 150 Supercab

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 Supercab

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

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  1. 1

    Cam phaser / VCT timing fault

    Medium severity

    A known cam-phaser timing issue on this engine family causes an audible rattle plus intermittent stall/stutter; on this truck the fault persisted after spark plugs, coils, and timing sensors were replaced and was only resolved by replacing the cam phasers and VCT solenoids.

    Reported in 2 NHTSA complaints
    Parts:cam phaserVCT solenoid
  2. 2

    Cylinder head valve guide defect (5.0L Coyote — TSB 19-2384)

    High severity

    A documented Ford TSB for this engine covers a cylinder-head valve-guide defect that produces a highway-speed misfire persisting even at idle, confirmed on this exact truck and requiring cylinder head/long-block replacement.

    Reported in 1 NHTSA complaint
    Parts:cylinder headvalve guides
  3. 3

    Carbon buildup causing valve/piston damage

    High severity

    One owner's engine failure was traced to excessive carbon buildup that cracked pistons and damaged the valves — carbon fouling on direct-injected engines can progress to a misfire and, if ignored, mechanical damage.

    Reported in 1 NHTSA complaint
    Parts:intake valves
  4. 4

    Worn or fouled spark plugs / weak ignition coils

    Low severity

    Spark plugs, sensor coils, and other ignition parts were replaced on this truck to chase a jerk/hesitate misfire condition — the most common misfire cause industry-wide.

    Reported in 1 NHTSA complaint
    Parts:spark plugsignition coil
  5. 5

    Timing chain tensioner failure

    High severity

    A broken timing chain tensioner on this engine caused a complete engine failure while in the dealer's possession; tensioner wear can produce rough running/misfire before catastrophic failure.

    Reported in 1 NHTSA complaint
    Parts:timing chain tensioner
  6. 6

    Exhaust manifold leak/cracking

    Medium severity

    Recurring cracked exhaust manifolds on this truck (replaced more than once) caused rough idling and power loss; while primarily an exhaust issue, the associated leak and airflow disruption can contribute to rough-running complaints.

    Reported in 1 NHTSA complaint
    Parts:exhaust manifold
  7. 7

    Clogged or leaking fuel injector

    Medium severity

    A partially clogged or dribbling injector unbalances that cylinder's air/fuel mixture; injector balance/flow testing isolates it.

    Common cause
    Parts:fuel injector
  8. 8

    Vacuum leak

    Medium severity

    Unmetered air entering after the MAF sensor leans a cylinder or bank enough to misfire, especially at idle.

    Common cause
    Parts:vacuum hose

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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

1

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.

2

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.

3

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.

4

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.

5

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 RoughFlashing Check Engine Light