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Rough Idle and Misfires on 2022 Ram 2500 6.4L Hemi

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Mark S. · rep 0 · May 22, 3:31 AM · 1 replies · solved · Question

Vehicle: 2022 Ram 2500 Laramie 6.4L Hemi

Hi all,

I'm having some issues with my 2022 Ram 2500 Laramie, which has the 6.4L Hemi engine. Recently, I've noticed a rough idle, and the engine occasionally misfires, especially when I'm accelerating or under load. It's thrown a Check Engine Light a couple of times, giving me P030x codes (specific cylinder misfires).

The truck only has about 35,000 miles on it, and I've kept up with all the maintenance. I'm really surprised to be having these kinds of engine problems so early. It feels like it's losing power and just not running smoothly.

Has anyone with a 6.4L Hemi in a newer Ram 2500 experienced similar misfire or rough idle issues? What was the cause, and what was the resolution? Could this be related to the MDS system, similar to the 5.7L?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:31 AM

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ClearTheCode admin answer:

Rough idle and misfires on a relatively new 2022 Ram 2500 with the 6.4L Hemi, especially with P030x codes, are concerning. While the 6.4L is a robust engine, it shares some design elements with the 5.7L, including the MDS system, which can be a source of issues.

Here are potential causes:

  1. MDS Lifter Failure: Similar to the 5.7L, the 6.4L Hemi uses MDS (Multi-Displacement System) lifters. A failing MDS lifter can cause a cylinder to misfire, leading to rough idle, ticking noises, and P030x codes. This is a significant concern and can lead to camshaft damage if not addressed.
  2. Spark Plugs/Ignition Coils: While less likely at 35,000 miles, a faulty spark plug or ignition coil on a specific cylinder can cause misfires. It's a simpler fix to rule out.
  3. Fuel Injector Issues: A clogged or faulty fuel injector for a specific cylinder can lead to an improper air/fuel mixture, resulting in a misfire.
  4. Valve Train Issues: Beyond lifters, other valve train components (e.g., valve springs, rocker arms) could be failing, though less common.
  5. PCM/ECM Software: Occasionally, a software glitch in the Powertrain Control Module (PCM) can cause misfire detection issues or incorrect engine management.

Diagnostics:

  • The P030x codes (e.g., P0301 for cylinder 1 misfire) are key. They point directly to the affected cylinder(s).
  • A compression test and leak-down test can help identify internal engine issues like valve or piston ring problems.
  • Using a professional scan tool, technicians can monitor misfire counts per cylinder and check fuel trims.

When to See a Shop: Given the low mileage and the potential for MDS lifter failure, it's critical to take your Ram to a dealership or a reputable mechanic immediately. This issue is often covered under the powertrain warranty. Continued driving with a misfiring cylinder, especially if it's due to a failing lifter, can cause severe and expensive engine damage. Do not delay diagnosis and repair.

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