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2009 Ram P0303: What It Means & Is It Safe to Drive?

P0303 on the 2009 Ram: Cylinder 3 Misfire Detected. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.

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What this code means

The PCM has detected a misfire specifically on cylinder 3. Diagnosis follows the same steps as P0301—swap parts to the same position on a known-good cylinder to isolate the fault.

Common causes on the 2009 Ram

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

Symptoms

  • Check Engine Light, often flashing under load
  • Rough idle or shaking
  • Loss of power, hesitation

Typical fixes

  • Replace spark plug and coil on cylinder 3
  • Test and replace fuel injector
  • Compression test if ignition parts don't resolve it

Repair cost range

For a 2009 Ram, repairs for P0303 typically fall between $150 and $900, depending on the root cause and labor rates in your area.

Known issues on Ram

Ram HEMI P0303 on cylinder 3 is a non-MDS cylinder. Coil or spark plug failure is the typical cause on high-mileage HEMI engines. On 6.4L HEMI Ram 2500, cylinder-specific misfires are rare but usually trace to a failed COP coil or a fouled plug from oil consumption.

Most commonly affected models

Ram 1500 5.7L HEMI 2009–2021Ram 2500 6.4L HEMI 2014–2021

Is it safe to keep driving your 2009 Ram with this code?

For driving-safety guidance—how far you can go, when to tow, and what's urgent—see these checklists:

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