P0306: Cylinder 6 Misfire Detected

A generic powertrain (engine and transmission) trouble code, same meaning on every brand.

Fix now, drive carefully

Short careful trips only - misfires under load do the most catalyst damage.

$20 - $700

typical repair range

NHTSA complaints mention this code

70,361

median mileage when reported, mi

Symptoms

Flashing check engine light on hills or when towing
Rough idle
Poor economy

Likely causes, most common first

Coil or plug on cylinder 6
Injector clogged
Intake manifold gasket leak
Low compression

Read P0306 yourself before paying for diagnosis

A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.

What is going on and how it gets diagnosed

P0306 is cylinder 6, which on a transverse V6 is often the hardest cylinder in the car to reach - rear bank, furthest from the accessible end. Labour, not parts, dominates the bill here.

That cost makes it worth confirming the diagnosis properly rather than replacing parts hopefully. Live misfire counters on a scan tool show whether cylinder 6 alone is affected or whether its whole bank is stumbling, which points at a shared cause such as a leaking intake gasket or a failing bank oxygen sensor rather than anything inside that one cylinder.

Repair options and cost

Spark plug$20 - $120

Ignition coil$100 - $350

Fuel injector$200 - $600

Intake gasket$250 - $700

Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.

Owner reports mentioning P0306

“Engine - The vehicle is available but the engine was replaced. I was able to get home however there was a potential for significant engine failure. Yes it was inspected by an independent service center. Yes it was inspected by an independent service center. A check engine light came on. Upon further inspection it was a Cylinder 6 misfire P0306. When the engine was inspected further by a mechanic it was determined that the cylinder wall was damaged and that coolant had entered the cylinder. Due to the extent of the engine damage the engine needed to be replaced.”2018 Jeep Wrangler · Mar 2026

“P0304 and P0306 misfiring and compression on both cylinders is 0. Both lifters have broke and collapsed. It started with a noise, once checked by the mechanic, we were told the lifter was going bad, before we could get it repaired it completely broke and that is when the check engine light came on and went off repeated times. At this time it is pouring out black smoke when driving and must have a complete engine replacement. The replacement work has been quoted for $10479.57.”2019 GMC Yukon XL · Jan 2026

“Check engine light on emissions system problem and transmission system problem, there is loss power of engine light, after 2 gear transmission feel like it jerks I don't have save to drive my car, i would like to request a recall to be inspected and repair by warranty of Honda because my car is defective by manufacturer Code are: P0420 (rear bank catalyst system efficiency below threshold [bank 1]) P0430 (front bank catalyst system efficiency below threshold [bank 2]) P0300-P0306 (misfire) P219A (air-fuel ratio variation of cylinder [bank 1, rear bank]) P219B (air-fuel ratio variation of cylinder [bank 2, front bank])”2016 Honda Pilot · May 2025

Show 7 more owner reports

“On April 1st my vehicles engine started normally and upon leaving the neighborhood began to rough idle. Prior to this, no lights were on and the vehicle had just passed an inspection. The engine was shuddering and there was very little power and the vehicle had difficulty maintaining speed. The codes were read and came back with P0304, P0306, P0302, P0300 and P0019. The vehicle was towed to a shop because it was undrivable. The vehicle is currently in the shop and they are recommending an entire engine replacement.”2016 Kia Sedona · Apr 2025

“I started getting a p0306 code on my truck on Thursday Jan 2, 2025. I took it to my mechanic and he said that it is a lower engine problem. On Saturday Jan 11,2025 there was a loud clunk from the engine and the vehicle lost power. My mechanic said that the connector rod broke. I contacted Honda but they said my vin is not in the recall and I would have to deal with the dealership. I know that they won't do anything so I am in the process of trying to install a used engine myself.”2017 Honda Ridgeline · Jan 2025 · 122,255 mi

“The engine began to fail because of a lack of adequate breathability into the crankcase, causing high crankcase pressure, excessive oil blowby, severe exhaust smoke, severe engine sludge, severe engine shuddering, and lack of response to the power steering because of engine power loss. The failure of the PCV system was at fault. Produced codes P0300, P0306, and P0430. Engine sludge needed to be cleaned, PCV hoses and PCV needed to be replaced, spark plugs needed to be replaced because of blowby, and valve covers also needed to be replaced because of sludge clogging the PCV baffles within the valve covers.”2018 Nissan Pathfinder · Nov 2024

“44110 miles. NO leaks, oil change every 2500 miles, all fluids are full and well maintained. Hard shift sometimes while in drive and accelerating. Engine light just came on yesterday with wife and 4 kids in vehicle, then engine light flashing. Pacifica felt sluggish and engine was rough. This happened driving on busy FREEWAY! Quickly pulled over at off ramp. Called tow and Mechanic neighbor pulled trouble code from ODB port using scanner P0306 which is engine misfire in cylinder 6. Car runs like crap and is unsafe to drive. Now need to tow to dealer for very expensive repair, just outside of 5 year warranty.”2017 Chrysler Pacifica · Mar 2024

“En algunos modelos Pilot 2016-2017, Ridgeline 2017 y Odyssey 2018, la luz indicadora de fallas (MIL) puede encenderse si uno de los siguientes códigos de diagnóstico de problemas (DTC) se almacena: P0420 (Eficiencia del sistema catalizador del banco trasero por debajo del umbral [banco 1]) P0430 (Eficiencia del sistema catalizador del banco delantero por debajo del umbral [banco 21) P0300-P0306 (falla de sincronización)”2017 Honda Pilot · Aug 2023

“Codes P06DD, P0456, P0306. mechanic said new motor is needed as there is a bad lifter, losing oil pressure and other issues. i have 133000 miles on my car. after further research, many other people with the Pentastar V6 engine have the same issues. a lawsuit was filed previously.”2014 Jeep Grand Cherokee · May 2023

“My car got recall from Honda on: ï· P0420 (rear bank catalyst system efficiency below threshold [bank 1]) ï· P0430 (front bank catalyst system efficiency below threshold [bank 2]) ï· P0300-P0306 (misfire) ï· P219A (air-fuel ratio variation of cylinder [bank 1, rear bank]) ï· P219B (air-fuel ratio variation of cylinder [bank 2, front bank]) but they fixed for P219A, and P219B only, now it still got issue on P0420 ( Catalyc conventer issue)”2016 Honda Pilot · Mar 2023

Cars that report P0306 most often

Based on mentions of this code in NHTSA owner complaints.

Frequently asked questions

Can I drive with P0306?

Short careful trips only - misfires under load do the most catalyst damage.

How much does it cost to fix P0306?

Typical US repair costs range from $20 for the simplest fix (spark plug) to $700 in the worst case. The right number depends on which cause your car has - see the causes list.

Related codes

The codes closest to P0306. They often appear together, and telling them apart is usually what narrows the diagnosis.

P0300Random/Multiple Cylinder Misfire Detected P0301Cylinder 1 Misfire Detected P0302Cylinder 2 Misfire Detected P0303Cylinder 3 Misfire Detected P0304Cylinder 4 Misfire Detected P0305Cylinder 5 Misfire Detected P0307Cylinder 7 Misfire Detected P0308Cylinder 8 Misfire Detected

Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.