P0302 on a Mazda: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

If the check engine light is flashing, stop driving, since a severe misfire can damage the catalytic converter.

What P0302 means on a Mazda

On a Mazda, P0302 means cylinder 2 is misfiring — it is not burning fuel the way it should. Because the code points to one fixed cylinder, the fault is usually in cylinder 2's spark plug, ignition coil, or fuel injector rather than a shared system.

Is P0302 common on Mazdas?

P0302 shows up on Mazda's SkyActiv-G 2.0L and 2.5L engines, common in the Mazda3, Mazda6, and CX-5. Ignition coils and spark plugs are the usual culprits, and on direct-injection SkyActiv engines, carbon buildup on intake valves can also cause misfires at higher mileage.

Commonly reported on: Mazda3, Mazda6, CX-5.

Symptoms

Check engine light on (flashing if severe)
Rough idle or shaking from the engine
Loss of power or hesitation when accelerating
Poor fuel economy

Common causes

most common: Worn or fouled spark plug in cylinder 2
common: Failing ignition coil on cylinder 2
common: Clogged fuel injector on cylinder 2
less common: Carbon buildup on intake valves (direct-injection engines)
less common: Low compression from engine wear

How to fix it

Fix	DIY?	Typical cost
Replace the spark plug in cylinder 2, or all of them	Yes	$40–150
Swap the ignition coil to another cylinder to confirm, then replace it	Yes	$80–300
Replace the faulty fuel injector	Mechanic	$150–600
Have intake valves cleaned of carbon buildup	Mechanic	$300–700

Frequently asked questions

Is it safe to drive my Mazda with a P0302 code?

Only if the check engine light is steady and the car runs okay. A flashing light means a severe misfire, so stop and get it towed.

What usually causes P0302 on a Mazda?

A bad spark plug or ignition coil on cylinder 2 is the most common cause. Clogged injectors and carbon buildup also cause it, especially on direct-injection SkyActiv engines.

How much does it cost to fix P0302 on a Mazda?

Most fixes run $40–$300. Spark plugs are cheapest, coils cost a bit more, and injector or carbon-cleaning jobs cost the most.