P0300 on a 2020 Honda Pilot

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 2020 Honda Pilot

Ranked from 472 NHTSA owner complaints filed for this vehicle.

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1
Spun/worn connecting rod bearings from oil-starvation related engine damage
High severity
A cluster of owners had rod-bearing failures (metal shavings, knocking, NHTSA Action PE25008) on this 3.5L engine, causing mechanical misfire from knock and lost cylinder compression.
Reported in 7 NHTSA complaints
2
Failing fuel injectors
Medium severity
Owners had 4-of-6 injectors fail or were diagnosed with injector-kit replacement per Honda's cylinder A/F test bulletins for P030x-family codes.
Reported in 3 NHTSA complaints
Parts:fuel injector
3
Low compression from worn rings/valves secondary to oil consumption/engine wear
High severity
Several complaints trace back to internal engine wear that also shows up as compression loss on affected cylinders.
Common cause
4
Worn spark plugs
Low severity
Standard high-mileage misfire cause on this engine; plugs should be checked/gapped as a routine first step.
Common cause
Parts:spark plug
5
Vacuum or intake air leak
Medium severity
Unmetered air disrupts the air-fuel mixture on one or more cylinders, producing an intermittent misfire.
Common cause
6
Carbon-fouled intake valves
Medium severity
Direct-injection engines like this one lack fuel washing the valves, so carbon buildup can disrupt airflow/sealing enough to misfire.
Common cause
7
EGR valve fault
Low severity
A stuck-open EGR valve dilutes the mixture at idle/low load enough to cause a misfire.
Common cause
Parts:EGR valve
8
Failing ignition coil
Medium severity
A weakening coil-on-plug unit drops spark energy to one cylinder, a classic single/random misfire cause.
Common cause
Parts:ignition coil

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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