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Rough Idle and Misfires on 2017 ILX

0

Tom H. · rep 0 · May 22, 4:55 AM · 1 replies · solved · Question

Vehicle: 2017 Acura ILX 2.4L

Hi everyone,

My 2017 Acura ILX with the 2.4L engine and about 70,000 miles has developed a really rough idle lately. It feels like the engine is shaking more than usual when I'm stopped at a light. On top of that, I've had the check engine light come on a few times, and when I scanned it, I got codes like P0301 and P0303, indicating misfires in cylinders 1 and 3.

Sometimes, the car also feels a bit sluggish during acceleration, and the fuel economy seems to have dropped slightly. I'm not sure if it's spark plugs, ignition coils, or something more serious. Any thoughts on what I should investigate first?

Thanks for your help!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:55 AM

0

Hello David R.,

Rough idle and specific cylinder misfire codes (P0301, P0303) on your 2017 Acura ILX 2.4L are clear indicators of an engine combustion issue. It's good that you've already scanned for codes, as this narrows down the possibilities significantly.

Here are the most common causes for these symptoms:

  1. Ignition System Components:
    • Spark Plugs: Worn or fouled spark plugs are a very common cause of misfires. At 70,000 miles, if they haven't been replaced, they are due or overdue. Start by inspecting and potentially replacing all spark plugs.
    • Ignition Coils: A failing ignition coil for a specific cylinder will cause a misfire in that cylinder. You can often swap coils between cylinders (e.g., move coil from cylinder 1 to cylinder 2) and see if the misfire code follows the coil to confirm if it's faulty.
  2. Fuel System Issues:
    • 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 might help if it's a minor clog, but a faulty injector needs replacement.
    • Low Fuel Pressure: While less likely to cause specific cylinder misfires, overall low fuel pressure could contribute to poor combustion (P0171 - System Too Lean).
  3. Engine Mechanical Issues:
    • Valve Clearance: Incorrect valve clearance can lead to poor compression and misfires. This is less common but possible, especially if maintenance has been neglected.
    • Compression Loss: In more severe cases, issues like a burnt valve or worn piston rings could cause a misfire due to low compression. A compression test would confirm this.

When to See a Shop: Given the specific misfire codes, you should address this promptly. Start by checking/replacing the spark plugs. If that doesn't resolve it, consider swapping ignition coils. If the problem persists, take your ILX to a trusted mechanic. They can perform a more detailed diagnosis, including fuel pressure tests, injector pulse tests, and potentially a compression test, to pinpoint the exact cause and prevent further engine damage.

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