P0300 on a 2023 Hyundai Palisade

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 2023 Hyundai Palisade

Ranked from 382 NHTSA owner complaints filed for this vehicle.

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1
Clogged or failing fuel injector(s)
Medium severity
Two owners on this exact vehicle had injectors replaced for a persistent check-engine/misfire complaint, with the dealer noting other Palisades in with the same issue.
Reported in 2 NHTSA complaints
Parts:fuel injector
2
Confirmed engine misfire with internal engine damage
High severity
One complaint explicitly describes a diagnosed misfire that progressed to a 'blown' engine needing replacement, indicating the misfire wasn't resolved by ignition parts alone.
Reported in 2 NHTSA complaints
Parts:fuel injector spark plug ignition coil
3
Worn spark plugs
Low severity
Extended plug gaps or fouling from age reduce spark energy and cause intermittent misfire, especially under load.
Common cause
Parts:spark plug
4
Failing ignition coil(s)
Medium severity
A coil breaking down under heat/load causes a repeatable single- or multi-cylinder misfire; swap-test a suspect coil to a known-good cylinder.
Common cause
Parts:ignition coil
5
Vacuum leak
Medium severity
Unmetered air from a cracked hose or intake gasket leans out one or more cylinders enough to misfire, usually worse at idle.
Common cause
6
Carbon-fouled intake valves (GDI buildup)
Low severity
Direct-injected engines build carbon on the backs of intake valves over time, disrupting airflow/fuel atomization enough to cause random misfire.
Common cause
7
EGR valve fault
Low severity
A stuck-open EGR valve dumps excess exhaust gas into the intake at idle/low load, diluting the charge enough to misfire.
Common cause
Parts: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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Matching symptoms

Car Runs Rough Flashing Check Engine Light