Trouble code · Powertrain · Generic (all makes)

P0303 Cylinder 3 Misfire Detected

Cylinder 3 is misfiring – the fuel in it isn't burning properly.

Safe to drive?
Drive with caution
Get it fixed soon
Scanner you need
Any OBD2 scanner
Even a basic code reader shows it
NHTSA complaints quoting it
269
Vehicle complaints, 2015–2025

Common causes

  • Worn spark plug or failing ignition coil on cylinder 3
  • Leaking or clogged fuel injector
  • Low compression

Symptoms

  • Rough idle, shaking, hesitation
  • The check engine light may flash

Can I drive with it?

Drive gently and get it fixed soon. If the light flashes, slow down and stop driving as soon as you safely can.

Tip: Swap the cylinder 3 coil with another cylinder's: if the misfire code follows the coil, replace the coil.

Which scanner reads it?

Any OBD2 scanner reads it.

Budget tools like the ANCEL AD310 read it; tools with live data and graphing – like the BlueDriver or OBDLink MX+ – help you find the cause. Not sure which fits you? Try the Find My Scanner quiz.

In the data

How common is it? At New York’s emissions inspections in 2020–21, P0303 was the #13 code found on cars that failed – 1.5% of all the codes found.

Of the vehicle complaints owners filed with NHTSA from 2015 to 2025, 269 quote P0303 – most often from Ford, Honda, Chrysler owners. Complaints lean toward serious problems, so treat this as a sign of how often the code turns up in real reports, not how often cars get it.

Both sources are compared on the Trends page.

General information to help you understand a code – not a diagnosis. Your car’s service information or a qualified mechanic has the final word. See how we research.