P0300 on a 2019 Chevrolet Silverado Ld 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 Ld 1500
Ranked from 822 NHTSA owner complaints filed for this vehicle.
- 1
AFM/DFM valve lifter roller failure (collapsed lifter, bent pushrod)
High severityA very large cluster of owners describe engine ticking, knocking, and shuddering diagnosed as collapsed lifters and a bent camshaft — GM's documented TSB PIP5776 lifter failure on this 5.3L EcoTec3 engine — leading directly to cylinder misfire.
Reported in 12 NHTSA complaints - 2
Oil starvation from ruptured engine oil cooler lines accelerating lifter/cam wear
Medium severityMultiple owners had oil cooler lines detach at the crimp joint, dumping oil pressure suddenly; the resulting marginal lubrication is a known contributor to the lifter/cam failures on this engine.
Reported in 5 NHTSA complaintsParts:oil cooler lines - 3
Camshaft phaser (VVT actuator) failure
Medium severityOwners report the variable valve timing actuator/phaser failing and needing dealer replacement, which disrupts valve timing enough to misfire.
Reported in 2 NHTSA complaintsParts:camshaft phaser - 4
Worn or fouled spark plugs
Medium severityStandard misfire-diagnostic first step; fouled plugs cause a weak or missed spark.
Common causeParts:spark plugs - 5
Failing ignition coil
Medium severityA weak coil-on-plug unit produces an intermittent, often cylinder-specific misfire.
Common causeParts:ignition coil - 6
Clogged or leaking fuel injector
Medium severityA partially clogged or dribbling injector starves or floods a cylinder.
Common causeParts:fuel injector - 7
Vacuum or intake leak
Low severityUnmetered air entering the intake leans out a cylinder enough to misfire.
Common cause - 8
Carbon-fouled intake valves
Low severityCarbon buildup disrupts valve sealing/airflow enough to misfire.
Common cause - 9
EGR valve fault
Low severityExcess or erratic exhaust gas recirculation dilutes the intake charge enough to 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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