P0300 on a 2022 Ram 1500 Classic Quad Cab

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 Ram 1500 Classic Quad Cab

Ranked from 588 NHTSA owner complaints filed for this vehicle.

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1
Fuel injector failure
High severity
A contact had the dealer diagnose an outright fuel injector failure after the check-engine light illuminated and the engine lost power/stalled.
Reported in 1 NHTSA complaint
Parts:fuel injector
2
MDS lifter/camshaft oil starvation (Hemi MDS)
High severity
An owner's dealer replaced the camshaft and oil-pan pickup for insufficient oiling to the Active Fuel Management/MDS lifters, a long-documented Hemi issue that can cause rough running and eventual cylinder misfire.
Reported in 1 NHTSA complaint
3
Worn or fouled spark plugs
Low severity
Aged or carbon-fouled plugs are the single most common cause of random/multi-cylinder misfire on the 5.7L Hemi; check gap and electrode wear.
Common cause
Parts:spark plugs
4
Failing ignition coil(s)
Medium severity
A weak or cracked coil-on-plug loses spark energy under load, producing an intermittent misfire on one or more cylinders.
Common cause
Parts:ignition coil
5
Vacuum or intake leak
Medium severity
Unmetered air entering after the MAF causes an erratic air-fuel ratio that can manifest as a misfire, especially at idle.
Common cause
Parts:intake gasket
6
Carbon-fouled intake valves
Low severity
Direct-injection engines are prone to carbon buildup on the backs of the intake valves, disrupting airflow/atomization into affected cylinders.
Common cause
7
Low cylinder compression (worn rings/valves)
High severity
Mechanical wear reducing a cylinder's compression prevents complete, consistent combustion and shows up as a misfire that a tune-up won't fix.
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