Dodge Durango III Rough Idle and Flickering Check Engine Light: What to Check First

When your Durango III's check engine light starts flickering off and on, usually while sitting at a stoplight, and the engine feels like it's stumbling or shaking, that's your 3.6L (or 5.7L) telling you it isn't firing cleanly at idle. In most cases you're dealing with a cylinder misfire, an air/fuel mixture issue, or a dirty/failing idle control system. The good news: many of these are fixable without replacing big assemblies if you catch them early.

What to check first

• Ignition coils and spark plugs – A worn plug or a failing coil (often on the Pentastar engine) will cause a misfire that shows up at idle. Each coil can be diagnosed and replaced individually — you rarely need to replace all six (or eight) unless they're all old. Swap the suspect coil with a neighboring cylinder to see if the misfire moves.
• Vacuum leaks – Cracked PCV hoses, a loose intake boot, or a failing intake manifold gasket let unmetered air in after the MAF sensor. That thins the mixture and makes idle rough. On the Durango III, listen for a hiss around the intake and check the rubber elbows near the throttle body.
• Throttle body and idle air control – Carbon buildup on the throttle blade can reduce airflow at idle, causing the PCM to hunt for idle speed. In many cases, removing the throttle body and cleaning it with intake cleaner restores smooth idle; the idle air control motor (on models that have one) can be cleaned or replaced separately.
• Intake air and MAF sensor – A dirty mass airflow sensor can cause intermittent lean/rich conditions. Use MAF cleaner and re-check; avoid touching the wire element.

Is it safe to keep driving?

If the light flickers only at idle and the engine still pulls normally, you can likely drive to a shop or parts store, but don't let it go on for long. A flashing/misfiring condition — even intermittent — can damage the catalytic converter if raw fuel is being dumped into the exhaust. If the light starts flashing continuously or the engine shakes hard under load, pull over and shut it down. Have the computer read for pending codes when you can, and confirm the exact coil, plug, or sensor part for your specific Durango's engine and model year before buying — some coil-on-plug setups and throttle bodies vary by emission level and trim.

This material is AI-generated and for informational purposes only — it does not replace an in-person diagnosis by a qualified mechanic.