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2018 Nissan Titan Pro-4X rough idle and misfire codes

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Mike T. · rep 0 · May 22, 2:48 AM · 1 replies · solved · Question

Vehicle: 2018 Nissan Titan Pro-4X

My 2018 Nissan Titan Pro-4X, with the 5.6L V8 engine and about 70,000 miles, has developed a really rough idle. It feels like the engine is shaking quite a bit when I'm stopped at a light or in park. The check engine light came on a few days ago, and I used my OBD scanner to pull the codes.

I'm getting P0300 (random/multiple cylinder misfire detected) and P0304 (cylinder 4 misfire detected). Sometimes it feels like it's struggling a bit under acceleration too, but the idle is the most noticeable problem. I've tried putting in premium fuel, but it hasn't made a difference.

Any ideas on what could be causing this? Could it be spark plugs, ignition coils, or something more serious like an injector issue? I'm hoping it's an easy fix.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 2:48 AM

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The P0300 and P0304 codes on your 2018 Nissan Titan Pro-4X indicate a misfire, specifically pointing to cylinder 4. This is a common issue that can stem from several components within the engine's ignition, fuel, or compression systems.

Common Causes & Diagnostics:

  1. Ignition System:
    • Spark Plugs: Worn or fouled spark plugs are a very common cause of misfires. Given your mileage, it's a good time to check them, especially cylinder 4's plug.
    • Ignition Coils: A failing ignition coil for cylinder 4 would directly cause a misfire. You can often swap coils between cylinders to see if the misfire code follows the coil.
  2. Fuel System:
    • Fuel Injector: A clogged or faulty fuel injector for cylinder 4 would prevent proper fuel delivery, leading to a misfire. This can be tested by a mechanic.
    • Fuel Pressure: Low fuel pressure across the rail could cause multiple misfires (P0300), but P0304 points more specifically to cylinder 4.
  3. Compression Issues: Less common, but a loss of compression in cylinder 4 (due to a bad valve, head gasket, or piston ring) would also cause a misfire. A compression test would confirm this.
  4. Vacuum Leaks: A vacuum leak near cylinder 4 could lean out the air/fuel mixture, causing a misfire.

When to See a Shop:

  • DIY Check: You can start by inspecting the spark plug and ignition coil for cylinder 4. If they look worn or damaged, replacing them might resolve the issue. Swapping the coil with another cylinder and re-scanning can help isolate if the coil is the culprit.
  • Professional Help: If basic checks don't resolve it, or if you're uncomfortable performing these checks, it's best to take your Titan to a mechanic. They have specialized tools to test fuel injectors, perform compression tests, and thoroughly diagnose the root cause. Driving with a persistent misfire can damage your catalytic converter over time, so addressing it promptly is important.
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