P0300 on a 2016 Nissan Altima

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 Nissan Altima

Ranked from 548 NHTSA owner complaints filed for this vehicle.

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1
Camshaft position sensor fault (recurring)
Medium severity
One owner's check-engine code was explicitly P0340 (camshaft position sensor), previously replaced and failing again; another owner's PCM cycled through cam/O2/throttle-body/fuel-pump codes alongside a rough, shaking idle before the engine refused to start.
Reported in 2 NHTSA complaints
Parts:camshaft position sensor
2
Mass airflow sensor fault / intake air leak
Medium severity
An independent shop replaced the MAF sensor and intake manifold after a shudder-and-non-response event, referencing Nissan TSB NTB16-121a.
Reported in 1 NHTSA complaint
Parts:mass airflow sensor intake manifold gasket
3
Worn spark plugs
Medium severity
Standard random-misfire cause; check plug gap and condition.
Common cause
Parts:spark plugs
4
Failing ignition coil(s)
Medium severity
Swap-test between cylinders to isolate.
Common cause
Parts:ignition coil
5
Clogged or leaking fuel injector(s)
Medium severity
Uneven spray/leak causes a lean or fouled cylinder.
Common cause
Parts:fuel injector
6
Vacuum leak
Medium severity
Unmetered air causes a lean misfire, worst at idle.
Common cause
7
Carbon-fouled intake valves
Low severity
Reduces and disrupts airflow/fuel atomization at the valve.
Common cause
8
EGR valve fault
Low severity
Excess EGR flow at idle can trigger random 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