P0300 on a 2019 Chevrolet Silverado 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 2019 Chevrolet Silverado 1500
Ranked from 1,035 NHTSA owner complaints filed for this vehicle.
- 1
Failed AFM/DFM Lifter and Camshaft Damage
High severityA collapsed or spun lifter in the Active Fuel Management (AFM) or Dynamic Fuel Management (DFM) system causes the intake or exhaust valve to stop actuating, leading to a dead cylinder misfire (P0300/P0305/P0307). This is confirmed by a loud ticking/popping noise, rough running, and inspection showing a damaged lifter and camshaft.
Reported in 8 NHTSA complaints - 2
Catastrophic Engine Failure (Connecting Rod/Main Bearing/Crankshaft)
High severityInternal lower engine failure, such as spun main or rod bearings, broken connecting rods, or crankshaft failure, causes severe knocking, loss of compression, and sudden stalling. This triggers misfire codes as the engine loses mechanical integrity.
Reported in 5 NHTSA complaints - 3
Faulty Spark Plugs or Ignition Coils
Low severityWorn or defective spark plugs, plug wires, or ignition coils fail to ignite the air/fuel mixture, causing a misfire. This is a standard diagnostic step and is confirmed by swapping coils/plugs or replacing them, though in these specific engines it is often a symptom of deeper mechanical failure.
Reported in 2 NHTSA complaints - 4
Fuel Delivery Issue (Low Fuel Pressure / Failing Injectors)
Medium severityA failing high-pressure fuel pump, fuel pump control module, or clogged fuel injectors prevent adequate fuel delivery, causing lean misfires. Confirmed by testing fuel pressure and injector pulse.
Reported in 1 NHTSA complaint - 5
Vacuum Leak / Intake Manifold Gasket Failure
Medium severityUnmetered air entering the engine leans out the air/fuel mixture, causing random misfires across multiple cylinders. Confirmed by checking fuel trims and performing a smoke test.
Common cause - 6
Mass Air Flow (MAF) Sensor Failure
Low severityA dirty or faulty MAF sensor incorrectly measures incoming air, causing the PCM to command the wrong fuel mixture, leading to random misfires. Confirmed by scanning MAF data and cleaning/replacing the sensor.
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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