Rough Idle & Check Engine Light on 2016 Grand Caravan SXT (P030X)

A rough idle and flashing check engine light with P0301 and P0303 codes (misfires on cylinders 1 and 3) on your 2016 Dodge Grand Caravan SXT (3.6L Pentastar) at 95,000 miles points strongly towards ignition system components. Here's a breakdown:

1. Spark Plugs:
   • Interval: For the 3.6L Pentastar, the recommended spark plug replacement interval is typically every 100,000 miles. At 95,000 miles, your plugs are definitely due and are a prime suspect for misfires.
   • Recommendation: Use OEM (Original Equipment Manufacturer) equivalent iridium or platinum plugs. NGK Iridium IX or Champion Iridium plugs are often recommended for these engines. Avoid copper plugs as they won't last as long.
2. Coil Packs: Each cylinder has its own coil pack on the 3.6L Pentastar. While plugs are the more common culprit at this mileage, a failing coil pack can also cause misfires. Since you have misfires on two specific cylinders, it's possible a coil pack for cylinder 1 or 3 is failing. You can swap the coil packs from cylinder 1 and 3 with known good ones (e.g., from cylinder 5 and 6) and see if the misfire codes follow the coil packs. If they do, you've identified a bad coil pack.
3. Other Potential Causes (Less Likely at this Mileage for P030X):
   • Fuel Injectors: A clogged or failing fuel injector could cause a misfire. You might notice a fuel smell or other symptoms.
   • PCV Valve: A faulty PCV valve can sometimes lead to vacuum leaks and rough idle, but less commonly direct misfire codes on specific cylinders.
   • Compression Issues: In rare cases, low compression in a cylinder can cause misfires, but this is usually accompanied by other symptoms and is less likely without other major engine problems.
4. DIY vs. Shop: Replacing spark plugs and coil packs on the 3.6L Pentastar is a common DIY job, though the rear bank of cylinders can be a bit challenging due to access. If you're comfortable, you can tackle it. If the issue persists after replacing the plugs and checking the coil packs, or if you're uncomfortable with the repair, it's best to take your van to a trusted mechanic for further diagnosis.