P0300 on a 2022 Ram 1500 Crew Cab Trx
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 Crew Cab Trx
Ranked from 588 NHTSA owner complaints filed for this vehicle.
- 1
MDS lifter/camshaft failure (oil-starved hydraulic roller lifters)
High severityOne owner's 5.7L HEMI MDS had already had the camshaft and oil-pan pickup replaced for lifter oil starvation and was awaiting a full engine replacement — a well-known HEMI "lifter tick" failure that produces a hard, often single-cylinder misfire.
Reported in 1 NHTSA complaint - 2
Fuel injector failure
Medium severityA dealer diagnosed a failed fuel injector after the check-engine light came on and the engine became inoperable, which can present as a dead or misfiring cylinder.
Reported in 1 NHTSA complaintParts:fuel injector - 3
Worn or fouled spark plugs
Medium severityExtended service intervals let plug gaps erode or deposits build up, weakening spark under load.
Common causeParts:spark plugs - 4
Failing ignition coil(s)
Medium severityA cracked boot or internal coil breakdown drops spark energy to one cylinder, especially under load or when hot.
Common causeParts:ignition coil - 5
Vacuum or intake air leak
Medium severityUnmetered air leaning out one or more cylinders causes an intermittent misfire, often worse at idle.
Common cause - 6
Low compression from worn piston rings or valves
High severityInternal wear reduces a cylinder's ability to build compression; confirm with a compression or leak-down test.
Common cause - 7
Carbon-fouled intake valves
Low severityDirect-injection engines don't wash the backs of the intake valves with fuel, so carbon buildup restricts and disrupts airflow into a cylinder.
Common cause - 8
EGR valve fault (stuck open)
Low severityExcess exhaust gas recirculated at the wrong time dilutes the intake charge and can trigger a misfire.
Common causeParts: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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