P0300 on a 2010 Chevrolet Silverado 1500 Extended 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 2010 Chevrolet Silverado 1500 Extended Cab

Ranked from 422 NHTSA owner complaints filed for this vehicle.

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1
Collapsed hydraulic lifter / AFM (Active Fuel Management) lifter failure
High severity
This is the single best-documented failure mode for the Gen IV 5.3L Vortec in this truck: five separate owners in this batch describe a tapping/ticking noise diagnosed as a collapsed lifter (several explicitly tied to the AFM/DOD cylinder-deactivation system), which kills a cylinder's valve action and produces a hard, persistent misfire.
Reported in 5 NHTSA complaints
Parts:hydraulic lifter camshaft
2
Worn spark plugs
Medium severity
One owner cycled through two full sets of plugs (and wires/coils) chasing a persistent cylinder-6 misfire, and another reported a rough, sputtering idle for about a minute after a cold start, both consistent with plug wear/fouling.
Reported in 2 NHTSA complaints
Parts:spark plug
3
Oil-fouled spark plugs from excessive oil consumption
High severity
This 5.3L is documented by its own dealer as a 'known problem' burning 3-4 quarts of oil between changes, with the oil specifically fouling the #7 spark plug and causing a loss of power, a well-known Gen IV Vortec issue.
Reported in 1 NHTSA complaint
Parts:spark plug
4
Low compression from worn piston rings
High severity
One owner's independent diagnosis and paperwork pointed to failing piston rings on the 5.3L causing a hard engine failure, matching a known ring-wear pattern reported across many trucks of this generation.
Reported in 1 NHTSA complaint
5
Failing ignition coil or spark plug wire
Medium severity
The same cylinder-6 misfire complaint specifically lists coils and wires among the parts swapped (twice) while chasing the fault.
Reported in 1 NHTSA complaint
Parts:ignition coil spark plug wire
6
Clogged or leaking fuel injector
Medium severity
The same persistent cylinder-6 misfire complaint lists fuel injectors among the parts replaced while troubleshooting.
Reported in 1 NHTSA complaint
Parts:fuel injector
7
Vacuum or intake leak
Medium severity
A rough, unsteady idle for roughly a minute after a cold start (before smoothing out once warm) is a pattern consistent with a small vacuum leak that closes up as components expand with heat.
Reported in 1 NHTSA complaint
8
Carbon-fouled valves
Low severity
Carbon buildup on intake valves disrupts airflow/fuel atomization and can trigger intermittent misfire.
Common cause
9
EGR valve fault
Low severity
A stuck-open EGR valve dilutes the intake charge too much at idle/low load, causing rough running and misfire.
Common cause
Parts: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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Matching symptoms

Car Runs Rough Flashing Check Engine Light