P0300 on a 2016 Kia Sorento

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 Kia Sorento

Ranked from 1,240 NHTSA owner complaints filed for this vehicle.

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1
Rod/main bearing failure from the engine oil-consumption defect (Theta II/Lambda GDI engine family)
High severity
This batch is dominated by Kia's well-documented GDI engine bearing-wear defect: metal debris/oil starvation wears the rod and main bearings, producing knocking, rough running, and stalling that precedes outright engine seizure. One complaint explicitly names the 2.4L Theta II engine and its known bearing-failure pattern; several others describe a knocking sound and check-engine light immediately before the engine locked up.
Reported in 15 NHTSA complaints
2
Head gasket failure allowing coolant into a cylinder
High severity
Two owners had the temperature gauge spike to HOT with visible engine-bay smoke, followed by a dealer diagnosis of head gasket and/or radiator failure with copper found in the engine - coolant reaching a cylinder disrupts combustion and can misfire before causing catastrophic damage.
Reported in 2 NHTSA complaints
Parts:head gasket
3
Worn spark plugs
Low severity
Standard wear item and a common source of a random misfire code.
Common cause
Parts:spark plugs
4
Failing ignition coil(s)
Medium severity
A weak or intermittent coil drops spark energy to a cylinder, especially under load.
Common cause
Parts:ignition coil
5
Clogged or leaking fuel injector(s)
Medium severity
A fouled or dribbling GDI injector unbalances the air/fuel mixture in a single cylinder.
Common cause
Parts:fuel injector
6
Vacuum leaks
Medium severity
Unmetered air entering downstream of the MAF leans a cylinder enough to misfire, most noticeable at idle.
Common cause
7
Carbon-fouled intake valves
Low severity
GDI engines with no port fuel washing the intake valves are prone to carbon buildup that disrupts airflow.
Common cause
8
EGR valve fault
Low severity
A stuck-open EGR valve over-dilutes the intake charge at idle/low load, producing a 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