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2018 Charger R/T Rough Idle and Misfire - CEL On

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Diana O. · rep 0 · May 22, 5:41 AM · 1 replies · solved · Question

Vehicle: 2018 Dodge Charger R/T

Hey everyone,

I'm having some trouble with my 2018 Dodge Charger R/T, 5.7L HEMI. Lately, it's developed a really rough idle, especially when I'm stopped at a light. It feels like the engine is shaking more than usual, and I can definitely feel some hesitation when I try to accelerate from a stop.

The check engine light came on a couple of days ago, and it's been on ever since. I haven't had a chance to get the codes read yet, but I'm guessing it's related to a misfire. The car just doesn't feel as smooth as it used to.

Has anyone else experienced this with their Charger? Any ideas on what might be causing it before I take it to the shop? I'm hoping it's something relatively simple.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:41 AM

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ClearTheCode admin answer:

It sounds like your 2018 Dodge Charger R/T is indeed experiencing an engine misfire, which is a common issue that triggers the Check Engine Light (CEL) and can cause rough idling and hesitation. The most likely OBD-II codes you'll find are P0300 (Random/Multiple Cylinder Misfire Detected) or specific P030X codes (e.g., P0301 for Cylinder 1 Misfire).

Here are the common causes and diagnostic steps:

  1. Ignition System Issues:

    • Spark Plugs: Worn, fouled, or incorrectly gapped spark plugs are a very common cause of misfires. They should be inspected and replaced if necessary, especially if they haven't been changed in a while.
    • Ignition Coils: A failing ignition coil can prevent a spark plug from firing correctly. If you have a specific P030X code, swapping the coil with another cylinder can help diagnose if the coil is the culprit.

  2. Fuel System Issues:

    • Fuel Injectors: A clogged or faulty fuel injector can lead to an insufficient amount of fuel reaching a cylinder, causing a misfire. Fuel injector cleaner can sometimes help, but a faulty injector may need replacement.
    • Fuel Pressure: Low fuel pressure due to a failing fuel pump or clogged fuel filter can cause multiple cylinder misfires.

  3. Air/Vacuum Leaks:

    • Vacuum Leaks: Unmetered air entering the engine through a cracked vacuum hose or intake manifold gasket can lean out the air-fuel mixture, leading to misfires.
    • PCV Valve: A faulty PCV valve can also contribute to vacuum leaks.

  4. Engine Mechanical Issues (Less Common but Possible):

    • Low Compression: Issues like worn piston rings, burnt valves, or a blown head gasket can cause a loss of compression in a cylinder, leading to a misfire. This is usually diagnosed with a compression test.

When to See a Shop:

  • Immediately: If the CEL is flashing, this indicates a severe misfire that could be damaging your catalytic converter. Drive as little as possible and get it to a shop right away.
  • Soon: If the CEL is solid and the car is running rough, it's best to have it diagnosed by a professional. While some basic checks can be done at home (like reading codes with an OBD-II scanner), pinpointing the exact cause of a misfire often requires specialized tools and expertise.
  • DIY Diagnostics: If you have an OBD-II scanner, read the codes first. This will give you a starting point. If it's a specific cylinder misfire (e.g., P0301), you can focus your inspection on that cylinder's spark plug and coil.
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