P0300 on a 2022 Jeep Wrangler Unlimited

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 2022 Jeep Wrangler Unlimited

Ranked from 371 NHTSA owner complaints filed for this vehicle.

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1
Fuel injector or high-pressure fuel pump failure
High severity
One owner had a failed fuel injector and high-pressure fuel pump that let fuel dilute the engine oil; a separate owner's fuel pump failed and stranded the vehicle - both point to fuel-delivery hardware as a misfire source on this platform.
Reported in 2 NHTSA complaints
Parts:fuel injector fuel pump
2
Valvetrain wear or timing-related mechanical noise
Medium severity
One owner reported a persistent ticking/knocking noise in the engine, which can accompany a mechanical misfire source.
Reported in 1 NHTSA complaint
3
Worn or fouled spark plugs
Low severity
Standard first check for any random/multiple-cylinder misfire on the 2.0L turbo engine used in this 4xe.
Common cause
Parts:spark plug
4
Failing ignition coils
Medium severity
A weak coil pack drops spark energy under load and is a common misfire source.
Common cause
Parts:ignition coil
5
Vacuum or intake leak
Medium severity
Unmetered air leans a cylinder enough to misfire; check hoses and intake boot connections.
Common cause
6
Carbon-fouled intake valves
Medium severity
Direct-injection turbo engines build carbon on valve backs over time, disrupting airflow and combustion.
Common cause
7
EGR valve fault
Low severity
A stuck-open EGR valve over-dilutes the intake charge at idle/light 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