P0300 on a 2016 Honda Accord

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 Honda Accord

Ranked from 591 NHTSA owner complaints filed for this vehicle.

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1
Weak or failing fuel pump (low- or high-pressure) reducing fuel delivery
High severity
Several owners describe sputtering/choking, stalling, and hesitation later diagnosed as a fuel pump fault (tied to Honda fuel-pump recall campaigns); insufficient pressure under load produces misfire, especially at low-to-mid RPM.
Reported in 4 NHTSA complaints
Parts:fuel pump
2
Rod bearing / connecting rod failure
High severity
Owners report bent connecting rod or seized bearing engine failures (matching Honda V6 recall 23V-751, and a similar report on a 4-cylinder engine) that produce audible knock and misfire before catastrophic seizure.
Reported in 2 NHTSA complaints
3
Worn spark plugs
Low severity
Degraded plug gap or fouling reduces spark energy, especially past 60-100k miles; a common baseline cause of random misfire.
Common cause
Parts:spark plug
4
Failing ignition coil
Medium severity
A weak coil-on-plug pack drops spark to a single cylinder; check for a cylinder-specific misfire code (P0301-P0306) to isolate.
Common cause
Parts:ignition coil
5
Clogged or leaking fuel injector
Medium severity
A dirty or dripping injector unbalances the air/fuel mixture in one cylinder; check injector balance rates on a scan tool.
Common cause
Parts:fuel injector
6
Vacuum or intake leak
Medium severity
Unmetered air entering after the MAF causes lean misfire, typically worse at idle; smoke-test intake boots and PCV hoses.
Common cause
7
Low compression (worn rings/valves)
High severity
Reduced cylinder sealing from wear lowers combustion efficiency enough to cause a misfire; a compression or leak-down test confirms.
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