P0300 on a 2017 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 2017 Ford F 250 Supercab
Ranked from 1,155 NHTSA owner complaints filed for this vehicle.
- 1
Low fuel rail pressure from high-pressure pump failure causing fuel-starvation misfire
High severityMultiple complaints on this exact vehicle report 'Low Fuel Pressure'/'Reduced Power' warnings, stalling, and a fuel filter full of metal shavings — insufficient fuel delivery to the injectors that manifests as a misfire.
Reported in 5 NHTSA complaints - 2
EGR system fault
Medium severityA dealer diagnosed a faulty EGR valve needing replacement on this vehicle after a persistent check-engine light.
Reported in 1 NHTSA complaintParts:EGR valve - 3
Worn or carbon-fouled spark plugs
Medium severityPlugs beyond service interval develop wide gaps or heavy carbon/oil fouling and misfire under load; pull and inspect gap and electrode wear on all cylinders.
Common causeParts:spark plugs - 4
Failing ignition coil(s)
Medium severityA cracked or heat-degraded coil produces a weak or intermittent spark on one cylinder; swapping the coil to a different cylinder and watching the misfire follow it confirms this.
Common causeParts:ignition coil - 5
Clogged or leaking fuel injector(s)
Medium severityA partially clogged or dribbling injector under- or over-fuels a cylinder; an injector balance/flow test isolates the bad one.
Common causeParts:fuel injector - 6
Vacuum or intake air leak
Medium severityUnmetered air entering after the airflow sensor leans one or more cylinders and destabilizes idle; smoke-test the intake tract, PCV, and brake booster hoses.
Common cause - 7
Carbon-fouled intake valves
Low severityDirect-injection engines build carbon deposits on the back of the intake valves that disrupt airflow and atomization, especially at idle/low RPM; confirmed with a borescope.
Common cause - 8
Low cylinder compression (worn rings/valves)
High severityMechanical wear that no ignition or fuel part will fix; a compression or leak-down test confirms it and points to internal engine repair.
Common cause - 9
EGR system fault
Medium severityA stuck-open EGR valve or passage dumps excess exhaust gas into the intake at idle/cruise and destabilizes combustion.
Common causeParts: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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