P0300 on a 2022 Ram 1500 Crew 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 Crew Cab
Ranked from 588 NHTSA owner complaints filed for this vehicle.
- 1
Fuel injector failure
High severityDealer explicitly diagnosed fuel injector failure after a check-engine light and mid-drive engine failure.
Reported in 1 NHTSA complaintParts:fuel injector - 2
5.7L HEMI MDS lifter / camshaft failure
High severityOwner reports collapsed MDS (Multi-Displacement System) lifters starving the camshaft of oil, a documented issue on 5.7L HEMI MDS engines that required cam and engine replacement; can produce rough-running/misfire symptoms.
Reported in 1 NHTSA complaint - 3
Intake manifold runner / swirl valve actuator failure
Medium severityOwner's truck was left undriveable waiting on a backordered swirl-valve/manifold-runner actuator, a part with a widely reported nationwide shortage on this engine; a stuck actuator disrupts cylinder airflow.
Reported in 1 NHTSA complaint - 4
Worn spark plugs
Medium severityCheck gap and electrode wear; a baseline cause of random misfire.
Common causeParts:spark plugs - 5
Failing ignition coil(s)
Medium severitySwap-test coils cylinder to cylinder to isolate a weak coil.
Common causeParts:ignition coil - 6
Vacuum/intake leak
Medium severityUnmetered air causes lean misfire, especially at idle.
Common cause - 7
Carbon-fouled intake valves
Medium severityDirect-injection engines accumulate carbon on valve backs, disrupting airflow.
Common cause - 8
Low compression (worn rings/valves)
High severityRun a compression or leak-down test on any cylinder that misfires consistently.
Common cause - 9
EGR valve fault
Low severityA stuck-open EGR valve dilutes the charge enough to misfire at idle/low load.
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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