P0300 on a Toyota Tacoma
P0300 means random/Multiple Cylinder Misfire Detected. On the Tacoma, a few causes come up far more than others.
What P0300 usually means on a Tacoma
P0300 on a Tacoma is a random or multi-cylinder misfire the ECU can't tie to one cylinder. On these engines the usual causes are overdue spark plugs and aging coils, along with the occasional vacuum leak. The V6s put the rear-bank coils and plugs under the intake, so they get neglected and are common misfire sources. Expect a rough idle, a stumble under load, and a flashing light if the misfire threatens the cat.
Most common causes on the Tacoma
- Worn spark plugs
The Tacoma's long-life plugs get overlooked, especially the hard-to-reach rear-bank set on the V6.
- Aging ignition coils
Denso coil-on-plug units weaken with heat and age and misfire across cylinders.
- Vacuum or PCV leak
A cracked hose leans all cylinders and reads as a random misfire.
- Carbon or injector deposits
Higher-mileage engines can accumulate deposits that upset combustion.
- Knock-related timing issues
On the V6, an unaddressed knock-sensor fault can pull timing and worsen rough running.
What P0300 costs to fix on a Tacoma
Plugs and coils are moderate parts, but on the Tacoma V6 the rear bank hides under the intake, so labor rises for those cylinders. The four-cylinder 2TR-FE is much easier to service. Diagnose which cylinders are affected before buying a full set of coils.
Fixing it
On a V6 Tacoma, do the full plug set while the intake is off rather than reaching in twice, and swap a suspect coil to a different cylinder to see whether the misfire follows it.
For the full step-by-step diagnosis order (any vehicle), see the main P0300 guide.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
Other codes on the Toyota Tacoma
Related symptoms
Toyota Tacoma problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0300 behavior is covered on the main P0300 page. Confirm with a scan tool before buying parts.
P0300 on your Tacoma?
Every problem becomes a Case. Tell Redline what your Tacoma is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.