Mazda CX-5 P0300: Random/Multiple Cylinder Misfire Detected

Severity: high Mazda CX-5 Most affected: 2013–2021 (Skyactiv-G 2.0/2.5)

Quick answer: On the Mazda CX-5 (Skyactiv-G), P0300 (random/multiple misfire) is most often caused by worn spark plugs or a failing ignition coil. The Skyactiv engine is generally reliable, so start with ignition basics and check for any vacuum leaks before deeper diagnosis.

TL;DR

Mazda CX-5 P0300: usually worn spark plugs or a failing ignition coil on the Skyactiv-G engine; vacuum leaks are secondary. Replace plugs/coils as needed. Typical shop cost: €120–€450 depending on the parts involved.

Why Mazda CX-5 owners get P0300

The CX-5’s naturally aspirated Skyactiv-G engine misfires most often from ignition wear — spark plugs due for replacement or a weakening coil. Its high compression ratio makes healthy plugs and coils important. Vacuum or intake leaks can cause lean misfires too. Checking for a cylinder-specific code (P0301–P0304) alongside P0300 helps separate a single failing coil from a shared cause like a vacuum leak.

Most likely causes on the CX-5

Likely cause	Probability	Notes
Worn spark plugs	40%	High-compression Skyactiv wants healthy plugs
Failing ignition coil	35%
Vacuum / intake leak (lean misfire)	25%

Mazda CX-5-specific known issues

Overdue spark plugs are a common P0300 cause on Skyactiv engines.
A single weak coil causes a wandering misfire — swap-test to confirm.
Vacuum/intake leaks can lean the mixture and trigger random misfires.

Mazda CX-5 P0300 repair cost

Typical shop cost (CX-5)	$120–$450
DIY range (generic)	$30–$300

Ranges vary by region, engine and parts grade.

Owner tips

Keep spark plugs on schedule — high-compression Skyactiv engines are sensitive to worn plugs.
Swap-test a suspect coil between cylinders to confirm it.
Smoke-test the intake if a lean code accompanies the misfire.

Confirm the code yourself: OBD-II scanners →

Full P0300 diagnostic guide

For the complete step-by-step diagnosis, all causes, and repair walkthrough that applies to every vehicle, see the main guide: P0300 — Random/Multiple Cylinder Misfire Detected.

Mazda CX-5 P0300 — FAQ

What causes P0300 on a Mazda CX-5?

Most often worn spark plugs or a failing ignition coil on the Skyactiv-G engine. Vacuum/intake leaks causing a lean misfire are a secondary cause.

How much is a P0300 fix on a CX-5?

Typically €120–€450 at a shop, depending on whether it needs plugs, a coil, or a vacuum-leak repair.

Can I drive my CX-5 with P0300?

If the light is flashing, stop to protect the converter. With a steady light, drive gently and address it soon.