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2017 Challenger SXT - Rough Idle & Misfire Codes P0301, P0303

0

Mike T. · rep 0 · May 22, 5:38 AM · 1 replies · solved · Question

Vehicle: 2017 Dodge Challenger SXT

Hey everyone,

My 2017 Dodge Challenger SXT (V6, 3.6L) with about 60,000 miles has developed a really rough idle lately. It feels like the engine is shaking more than usual, especially when stopped at a light. The Check Engine Light came on, and when I scanned it, I got P0301 and P0303, indicating misfires on cylinders 1 and 3.

I haven't noticed any significant loss of power while driving, but the rough idle is definitely annoying. I'm wondering if this is a common issue for these engines and what the usual culprits are. Could it be spark plugs, ignition coils, or something more serious?

Any advice on where to start troubleshooting would be great. Thanks in advance!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:38 AM

0

ClearTheCode admin answer:

The P0301 and P0303 codes on your 2017 Dodge Challenger SXT indicate misfires specifically on cylinders 1 and 3. This is a common diagnostic scenario, and while it can be frustrating, there's a clear path to troubleshooting.

Here are the most common causes for misfires in specific cylinders:

  1. Ignition System:
    • Spark Plugs: Worn or fouled spark plugs are a very common cause of misfires. Given your mileage, it's a good time to check them, especially if they haven't been replaced recently.
    • Ignition Coils: Each cylinder has its own ignition coil. A failing coil for cylinder 1 or 3 would directly cause a misfire. You can often swap coils between cylinders to see if the misfire code follows the coil.
  2. Fuel System:
    • Fuel Injectors: A clogged or faulty fuel injector for cylinder 1 or 3 would prevent proper fuel delivery, leading to a misfire. Fuel injector cleaner can sometimes help, but a failing injector might need replacement.
    • Low Fuel Pressure: While less likely to affect only specific cylinders, overall low fuel pressure could contribute to misfires.
  3. Compression Issues:
    • Low Compression: This is more serious and could indicate issues like worn piston rings, a faulty valve, or a head gasket problem. A compression test would be needed to diagnose this.
  4. Vacuum Leaks: While often causing multiple cylinder misfires or lean codes, a vacuum leak near a specific cylinder could potentially contribute.

When to see a shop:

  • Persistent Misfires: If swapping coils or replacing spark plugs doesn't resolve the issue, or if you're uncomfortable performing these tasks, a professional diagnosis is recommended.
  • Fuel System Testing: Diagnosing fuel injector issues or fuel pressure problems requires specialized tools and expertise.
  • Compression Test: If ignition and fuel systems check out, a shop can perform a compression test to rule out internal engine problems, which are more complex to repair.
  • Advanced Diagnostics: A shop can use a scan tool to monitor live data, such as fuel trims and O2 sensor readings, to get a clearer picture of what's causing the misfires.
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