P0300 on a 2010 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 2010 Chevrolet Malibu
Ranked from 1,360 NHTSA owner complaints filed for this vehicle.
- 1
Timing chain wear, stretch, or failure
High severityMultiple owners had the timing chain replaced (one chain broke and 'smashed all the valves'); this GM 2.4L Ecotec is known for plastic timing-chain-guide wear that causes rough running and misfire before outright failure.
Reported in 3 NHTSA complaints - 2
Worn spark plugs
Medium severitySpark plugs were replaced (along with wires/coils) multiple times in this batch while owners chased stalling/misfire-like symptoms.
Reported in 3 NHTSA complaintsParts:spark plug - 3
Camshaft or crankshaft position sensor/circuit fault
Medium severityOne complaint explicitly cites a camshaft position sensor/circuit fault, which can produce misfire-like running and timing-correlation codes.
Reported in 1 NHTSA complaintParts:camshaft position sensor - 4
Failing ignition coils
Medium severityA weak or intermittently-failing coil produces a misfire on the affected cylinder(s).
Common causeParts:ignition coil - 5
Clogged or leaking fuel injectors
Medium severityAn uneven spray pattern from a dirty or leaking injector disrupts combustion on that cylinder.
Common causeParts:fuel injector - 6
Vacuum or intake leak
Medium severityUnmetered air entering the intake leans a cylinder or bank enough to misfire.
Common cause - 7
Carbon-fouled valves
Low severityCarbon buildup on intake valves disrupts airflow and can cause a rough-running misfire.
Common cause - 8
Low compression from worn rings or valves
Low severityReduced cylinder sealing lowers combustion efficiency enough to misfire under load.
Common cause - 9
EGR valve fault
Low severityA stuck-open EGR valve introduces excess exhaust gas that destabilizes combustion, especially at idle.
Common causeParts:EGR valve
Part links go to Amazon search results for this vehicle. As an Amazon Associate, WrenchConnect earns from qualifying purchases — always confirm fitment for your exact trim and engine before ordering.
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.
Rather have a pro handle it? Find a vetted local mechanic.