P0300 on a 2017 Toyota Tacoma
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 2017 Toyota Tacoma
Ranked from 237 NHTSA owner complaints filed for this vehicle.
- 1
Faulty Spark Plugs / Ignition Coils
Medium severityA common cause for misfires (P0300/P0301-P0306). Look for worn plugs or failed coils causing poor combustion.
Reported in 2 NHTSA complaints - 2
Intake Manifold ACIS Flap Failure
High severityThe Acoustic Control Induction System (ACIS) flap inside the intake manifold can detach or break, causing severe misfires, limp mode, and potential internal engine damage.
Reported in 2 NHTSA complaints - 3
Crankshaft Position Sensor Failure
Medium severityA faulty crank sensor can cause stalling, rough running, and misfire codes by failing to accurately report engine position.
Reported in 2 NHTSA complaints - 4
Cylinder Head Gasket Leak / Warped Cylinder Head
High severityCoolant leaking into the combustion chamber or loss of compression due to head warping can cause persistent misfires.
Reported in 1 NHTSA complaint - 5
Loss of Engine Compression (Internal Engine Failure)
High severityZero compression in cylinders (e.g., #5 and #6) will cause severe misfires and require engine replacement.
Reported in 1 NHTSA complaint - 6
Vacuum Leak / Intake Manifold Gasket Leak
Medium severityUnmetered air entering the engine leans out the air/fuel mixture, causing random misfires.
Common cause - 7
Fuel Injector Failure
Medium severityClogged or failed fuel injectors prevent proper fuel delivery, leading to lean misfires.
Common cause - 8
Low Fuel Pressure
Medium severityA failing fuel pump or clogged fuel filter can starve the engine of fuel, causing random misfires across multiple cylinders.
Common cause
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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