P0300 on a 2013 Ram 1500

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 2013 Ram 1500

Ranked from 1,254 NHTSA owner complaints filed for this vehicle.

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1
Camshaft and Lifter Failure (MDS Lifter Collapse)
High severity
The 5.7L Hemi is notorious for lifter roller bearings failing and wearing down the camshaft lobes, often related to the Multi-Displacement System (MDS) or oil starvation. This causes severe misfires, a loud ticking noise, and can lead to catastrophic engine failure with metal debris in the oil.
Reported in 12 NHTSA complaints
2
Broken Exhaust Manifold Bolts / Warped Exhaust Manifold
Medium severity
The exhaust manifolds on the 5.7L engine frequently warp, snapping the rear manifold bolts and causing an exhaust leak. While primarily causing a ticking sound and exhaust smell, severe leaks can skew oxygen sensor readings and contribute to misfire or engine unbalance codes.
Reported in 7 NHTSA complaints
3
Worn Spark Plugs or Faulty Ignition Coils
Low severity
Worn spark plugs or failing ignition coil packs are standard causes for a P0300 random misfire code. Replacing the plugs and coils is often the first diagnostic step before tearing into the engine for mechanical failures.
Reported in 2 NHTSA complaints
4
Faulty Fuel Injectors
Medium severity
A clogged or failing fuel injector can starve a cylinder of fuel, leading to a lean misfire. Diagnostics usually involve checking injector pulse and flow rates.
Reported in 1 NHTSA complaint
5
Intake Manifold Gasket / Vacuum Leak
Medium severity
Unmetered air entering the engine through a leaking intake manifold gasket or vacuum hose can cause a lean condition, resulting in random multiple cylinder misfires.
Reported in 1 NHTSA complaint
6
Faulty Oxygen (O2) Sensor
Low severity
A degraded or failing O2 sensor can cause the engine control module to incorrectly adjust the air/fuel mixture, leading to poor running conditions and random misfires.
Reported in 1 NHTSA complaint
7
Low Fuel Pressure / Failing Fuel Pump
Medium severity
If the fuel pump is failing or the fuel filter is clogged, the engine will not receive adequate fuel pressure under load, causing random misfires across multiple cylinders.
Common cause
8
Faulty MAP Sensor
Low severity
A malfunctioning Manifold Absolute Pressure (MAP) sensor provides incorrect engine load data to the PCM, which can throw off fueling and ignition timing, resulting in a P0300 code.
Common cause

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