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2020 Aviator Rough Idle & Check Engine Light - P0303

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Ryan M. · rep 0 · May 22, 8:18 AM · 1 replies · solved · Question

Vehicle: 2020 Lincoln Aviator Reserve

My 2020 Lincoln Aviator Reserve, with about 60k miles, has recently started acting up. When I'm at a stop light, the engine feels like it's shaking a bit more than usual, and sometimes there's a slight hesitation when I accelerate from a stop.

The check engine light came on yesterday. I ran a quick scan with my OBD-II reader and got a P0303 code, indicating a misfire on cylinder 3.

Has anyone experienced this with their Aviator? What was the fix? I'm hoping it's something simple like a spark plug or coil before I have to take it to the dealer.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 8:18 AM

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ClearTheCode admin answer:

A P0303 code on your 2020 Lincoln Aviator Reserve indicates a misfire detected in cylinder 3. This is a common issue across many modern direct-injection engines, including the 3.0L EcoBoost found in your Aviator. Addressing it promptly is important to prevent further damage, especially to the catalytic converter.

Here are the common causes and diagnostic steps:

  1. Spark Plug Issue: The most frequent culprit. Over time, spark plugs wear down, leading to an inconsistent spark. Given your 60k mileage, it's a good time to consider spark plug replacement if they haven't been done.
  2. Ignition Coil Failure: The ignition coil for cylinder 3 might be failing. Coils provide the high voltage needed for the spark plug to fire.
  3. Fuel Injector Problem: A clogged or faulty fuel injector for cylinder 3 could be delivering too much, too little, or an incorrect spray pattern of fuel, leading to a misfire.
  4. Vacuum Leak: Less common for a single cylinder misfire, but a localized vacuum leak near cylinder 3 could lean out the air-fuel mixture.
  5. Low Compression: In rare cases, internal engine issues like worn piston rings or valve problems can cause low compression in a cylinder, leading to a misfire.

Diagnostic Steps You Can Take:

  1. Verify the Code: Confirm P0303 is the only active code. Sometimes other codes can point to a broader issue.
  2. Inspect Spark Plug and Coil: Carefully remove the ignition coil and spark plug from cylinder 3. Look for signs of wear, oil fouling, or damage.
  3. Swap Components (Diagnostic Test):
    • Ignition Coil: Swap the ignition coil from cylinder 3 with a coil from a different, healthy cylinder (e.g., cylinder 1). Clear the codes and drive the vehicle. If the misfire code changes to P0301 (misfire on cylinder 1), you've identified a faulty ignition coil.
    • Spark Plug: If the coil swap doesn't move the misfire, try swapping the spark plug from cylinder 3 with one from another cylinder. If the misfire moves, the spark plug is the issue.
  4. Fuel Injector Check: If the misfire doesn't move after swapping coils and plugs, a fuel injector issue is highly probable. This usually requires specialized tools or a professional to test injector pulse and spray pattern.

When to See a Shop:

  • If you're not comfortable performing the diagnostic swaps yourself.
  • If swapping the spark plug and coil does not resolve the issue or move the misfire to a different cylinder.
  • If the misfire is persistent and causes significant drivability issues, as continued driving with a misfire can damage your catalytic converter, which is an expensive repair.
  • If you suspect a fuel injector problem or internal engine issue (low compression), as these require professional tools and expertise.
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