P0300 on a 2019 Ford F 250 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 2019 Ford F 250 Supercab

Ranked from 1,151 NHTSA owner complaints filed for this vehicle.

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1
Low fuel rail pressure from a failing lift pump or fuel pump module
Medium severity
Several owners had no-start/long-crank or sudden stall events linked to failing fuel delivery components, which can starve individual cylinders enough to register as a misfire.
Reported in 3 NHTSA complaints
Parts:fuel lift pump fuel filter
2
Charge air cooler (CAC) hose failure or intake boost leak
Medium severity
A dealer diagnosed a failed charge air cooler hose after the truck lost power with a Mass Air Flow Sensor message and visible smoke; a boost/charge-air leak upsets the air-fuel charge and can present as a running/misfire complaint.
Reported in 2 NHTSA complaints
Parts:charge air cooler hose intake boot
3
High-pressure fuel injection pump (CP4) failure contaminating the fuel system
High severity
A defective fuel injection pump was diagnosed after catastrophic engine damage on one of these trucks (over $17,000 in repairs) — metal debris from a failing CP4-style pump contaminates injectors and starves/upsets combustion, producing misfire-type running issues.
Reported in 1 NHTSA complaint
Parts:high-pressure fuel pump fuel injector
4
Rocker arm / valvetrain failure (6.7L Powerstroke known issue)
High severity
An owner documented a rocker arm failure causing significant running problems on this engine, a recognized 6.7L Powerstroke valvetrain wear issue that disrupts normal cylinder combustion.
Reported in 1 NHTSA complaint
Parts:rocker arm
5
Fuel injector failure or fouling
Medium severity
A common secondary effect of injection pump contamination on this engine; a fouled or stuck injector produces a cylinder-specific misfire.
Common cause
Parts:fuel injector
6
Glow plug failure
Low severity
A failed glow plug on a cold-natured diesel can cause a cylinder to misfire or fail to light off during cold starts.
Common cause
Parts:glow plug
7
EGR valve fault
Low severity
A stuck or leaking EGR valve over-dilutes the intake charge on one or more cylinders, producing a misfire-like running condition.
Common cause
Parts:EGR valve
8
Low compression from worn rings/valves
Medium severity
Mechanical wear reduces a cylinder's ability to build compression, producing a persistent misfire that no fuel or electrical repair will fix.
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