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2021 Titan Check Engine Light - P0301, P0303 Misfire Codes

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Kim L. · rep 0 · May 22, 2:49 AM · 1 replies · solved · Question

Vehicle: 2021 Nissan Titan Pro-4X

Hey everyone,

My 2021 Nissan Titan Pro-4X, with about 35,000 miles, just threw a Check Engine Light. It's also running pretty rough, especially at idle, and I can feel a noticeable loss of power. I pulled the codes with my scanner, and I'm getting P0301 (Cylinder 1 Misfire Detected) and P0303 (Cylinder 3 Misfire Detected).

This is a V8 engine, so two cylinders misfiring at once is concerning. I'm thinking spark plugs or ignition coils, but it seems odd for two to go bad simultaneously. Could it be something else, like fuel injectors or even a vacuum leak affecting multiple cylinders on the same bank? I haven't noticed any strange smells or smoke.

Any insights or common issues with the Titan's V8 that could cause this? Thanks in advance!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 2:49 AM

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ClearTheCode admin answer:

Multiple misfire codes (P0301, P0303) on your 2021 Nissan Titan's V8 indicate a significant issue affecting combustion in those specific cylinders. While it's possible for multiple ignition coils or spark plugs to fail, it's less common for them to do so simultaneously without a common underlying cause.

Here's a systematic approach to diagnose the problem:

  1. Check Ignition System:
    • Spark Plugs: While 35,000 miles is a bit early for spark plug failure, inspect the plugs from cylinders 1 and 3. Look for fouling, wear, or damage. If they look bad, consider replacing all plugs.
    • Ignition Coils: Swap the ignition coils from cylinders 1 and 3 with known good coils from other cylinders (e.g., 5 and 7). If the misfire codes follow the coils to the new cylinders, the coils are faulty.
  2. Check Fuel System:
    • Fuel Injectors: A clogged or faulty fuel injector in cylinders 1 and 3 could cause misfires. You can test injector resistance or listen to them with a stethoscope for proper operation. Fuel injector cleaner might help if they're just dirty, but a faulty one will need replacement.
    • Fuel Pressure: Low fuel pressure could cause a lean condition leading to misfires, but typically this would affect more cylinders or cause a lean code (P0171/P0174) first.
  3. Check Air/Vacuum Leaks: A significant vacuum leak could affect multiple cylinders, but it's less likely to be isolated to just cylinders 1 and 3 without affecting others on the same bank or causing a lean condition code.
  4. Compression Test: If all else fails, a compression test on cylinders 1 and 3 will determine if there's an internal engine issue (e.g., valve problem, head gasket) causing low compression and thus misfires.

When to See a Shop:

  • If swapping coils or replacing spark plugs doesn't resolve the issue.
  • If you suspect a faulty fuel injector, as these can be tricky to diagnose and replace without proper tools.
  • If a compression test indicates low compression, as this points to a more serious internal engine problem requiring professional repair.
  • A professional shop can perform advanced diagnostics, including fuel pressure tests, injector pulse width analysis, and cylinder contribution tests, to pinpoint the exact cause.
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