P0300 on a 2016 Chevrolet Malibu

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 2016 Chevrolet Malibu

Ranked from 859 NHTSA owner complaints filed for this vehicle.

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1
Cracked piston from Stochastic Pre-Ignition (SPI) on the 1.5L LFV turbo engine
High severity
A complaint documents a borescope finding of scuffed cylinder walls and a cracked piston tied to GM's Stochastic Pre-Ignition recall (17019) and follow-up SPI monitoring campaign (N182195660) on the 1.5L LFV turbo engine in these 2016-2017 Malibus; SPI causes rough running and misfire before it cracks a piston. A second complaint on the same platform reported a P0302 cylinder-2 misfire ultimately attributed to the pistons and referenced the same SPI campaign.
Reported in 2 NHTSA complaints
2
Vacuum-pump debris contaminating the timing chain/camshaft
Medium severity
Two complaints describe the auxiliary brake-vacuum pump breaking and shedding debris into the camshaft/timing-chain area, causing internal engine damage; wear or timing disruption from this failure can produce a misfire.
Reported in 2 NHTSA complaints
Parts:vacuum pump
3
High-pressure fuel pump detaching from the cylinder head (GM Recall 18V-358)
High severity
A complaint describes the HPFP's mounting bolts breaking or coming loose and the pump detaching from the cylinder head, matching GM Recall 18V-358, with weeks of engine misfires and a sudden loss of power leading up to the failure.
Reported in 1 NHTSA complaint
Parts:high-pressure fuel pump fuel pump mounting bolts
4
Fuel injector O-ring/backing-ring failure leaking fuel onto a hot cylinder
High severity
A complaint describes the injector backing ring failing, letting the O-ring dislodge and leak high-pressure fuel onto the cylinder next to the ignition coil, explicitly reported as causing misfire, bad fuel smell, and a fire hazard.
Reported in 1 NHTSA complaint
Parts:fuel injector injector seal kit
5
Worn spark plugs or a weak ignition coil
Medium severity
Degraded plugs or coils cause an intermittent spark-side misfire that typically worsens under load.
Common cause
Parts:spark plugs ignition coil
6
Vacuum or intake leak
Medium severity
Unmetered air entering after the MAF leans one or more cylinders enough to misfire, most noticeable at idle.
Common cause
Parts:intake gasket
7
Carbon-fouled intake valves
Medium severity
This direct-injection engine accumulates intake-valve deposits over time that disturb airflow and combustion at individual cylinders.
Common cause
8
Low compression from worn rings or valves
Medium severity
General cylinder wear reduces sealing enough that a cylinder can't sustain a clean burn, especially at idle.
Common cause

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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