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2021
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Rough Idle or Engine Misfire

Expert diagnosis and repair solutions for 2021 ram 1500 Rough Idle or Engine Misfire. Get step-by-step fixes, cost estimates, and professional advice.

Expert Repair Solutions

1
medium$150-$300
Replace faulty spark plugs and ignition coils to resolve misfire and rough idle.
Source: https://repairpal.com/ram/1500/2021/rough-idle

Repair Steps:

  1. Diagnose the engine to identify faulty spark plugs and ignition coils.
  2. Purchase OEM or high-quality aftermarket spark plugs and ignition coils.
  3. Remove the old spark plugs and ignition coils.
  4. Install the new spark plugs and ignition coils.
  5. Test the engine to ensure the misfire and rough idle are resolved.
2
medium$200-$500
Clean or replace fuel injectors to address rough idle issues.
Source: https://5thgenrams.com/community/threads/engine-troubles-rough-idle.33412/

Repair Steps:

  1. Perform a diagnostic scan to confirm fuel injector issues.
  2. Use a fuel injector cleaning kit to clean the injectors.
  3. If cleaning does not resolve the issue, replace the faulty fuel injectors.
  4. Reassemble the fuel system and test the engine for improvements.
3
hard$300-$600
Perform wiring harness modification as per TSB 0810921 to fix engine misfire.
Source: https://static.nhtsa.gov/odi/tsbs/2025/MC-11013168-0001.pdf

Repair Steps:

  1. Locate the engine ground harness and identify the wiring harness eyelet.
  2. Cut off the existing eyelet and splice in a new pigtail.
  3. Secure the new connection and ensure proper grounding.
  4. Clear any diagnostic trouble codes (DTCs) and test the engine for misfire resolution.

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