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2018 NSX Engine Misfire and Rough Idle with CEL

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Mike T. · rep 0 · May 26, 3:59 AM · 1 replies · solved · Question

Vehicle: 2018 Acura NSX

My 2018 Acura NSX has suddenly developed a rough idle and a noticeable engine misfire, especially when I'm stopped at a light. The 'Check Engine Light' (CEL) came on yesterday and hasn't gone off. The car feels a bit hesitant under acceleration too.

I'm concerned about driving it like this. Has anyone with a 2016-2026 NSX experienced similar engine issues? What should I be looking for, and what are the common culprits for misfires in these engines?

Any advice on troubleshooting or what to expect would be greatly appreciated. I want to get this fixed quickly.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 26, 3:59 AM

0

ClearTheCode admin answer:

An engine misfire, rough idle, and an illuminated Check Engine Light (CEL) in your 2018 Acura NSX are clear indicators of an engine performance problem that needs prompt attention. Misfires can damage catalytic converters if left unaddressed.

Here's a systematic approach to diagnosing and addressing this:

  1. Retrieve OBD-II Codes: The first and most critical step is to scan your NSX for diagnostic trouble codes (DTCs). Common codes for misfires include:
    • P0300: Random/Multiple Cylinder Misfire Detected.
    • P030X: Cylinder X Misfire Detected (e.g., P0301 for Cylinder 1, P0302 for Cylinder 2, etc.). This code will tell you which specific cylinder(s) are misfiring.
  2. Common Causes for Misfires: Once you have the specific cylinder code, you can narrow down the potential causes:
    • Ignition System: Faulty spark plug, worn spark plug, or a failing ignition coil for the affected cylinder. These are very common.
    • Fuel System: Clogged or faulty fuel injector for that cylinder, low fuel pressure, or contaminated fuel.
    • Air/Compression Issues: A vacuum leak near that cylinder, low compression in the cylinder (due to valve issues or piston rings), or a dirty air filter.
    • Sensors: Less common for a single-cylinder misfire, but a faulty Mass Air Flow (MAF) sensor or Oxygen (O2) sensor can cause general engine performance issues that might lead to misfires.
  3. Troubleshooting Steps: If you have a specific cylinder code, you can swap the spark plug and ignition coil from the misfiring cylinder to a known good cylinder. If the misfire code follows the component, you've found the culprit.
  4. When to See a Shop: If you're not comfortable performing these checks yourself, or if the problem persists after basic troubleshooting, take your 2018 Acura NSX to an Acura dealership or a reputable performance shop. They have the advanced diagnostic tools to accurately identify the misfire's cause, perform compression tests, and ensure the direct injection system is functioning correctly. Driving with a persistent misfire can lead to more severe engine damage or catalytic converter failure.
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