2021 Infiniti QX60 VQ35 Misfire with P0301: Cylinder 1 Diagnosis Guide

The 2021 Infiniti QX60's VQ35DE engine has earned a reputation for smooth, reliable operation over Nissan's decades of refinement. When P0301 appears indicating cylinder 1 misfire, this normally silky V6 develops an unwelcome roughness. The good news: cylinder-specific codes like P0301 narrow diagnosis significantly.

Cylinder 1 Location

In the VQ35DE's V-configuration, cylinder 1 sits at the front of the driver-side bank. This location is relatively accessible for inspection and testing, simplifying diagnosis compared to rear cylinders.

Symptoms of Cylinder 1 Misfire

• Rhythmic roughness at idle—consistent with one-cylinder pattern
• Check engine light on (steady or flashing if severe)
• Vibration through seats and steering
• Reduced power and acceleration
• Possible fuel smell from unburned mixture

Primary Causes

Ignition Coil Failure

The VQ35DE uses individual coil-on-plug ignition. Cylinder 1's coil can fail independently from heat stress, age, or manufacturing defect.

Spark Plug Issues

Worn electrodes, improper gap, or carbon fouling on the cylinder 1 plug causes misfires even if the coil is functional.

Fuel Injector Problems

Clogged, leaking, or electrically failed injectors prevent proper fuel delivery to cylinder 1.

Compression Loss

Less common on lower-mileage vehicles, but valve or piston ring issues affecting only cylinder 1 can cause isolated misfires.

The Swap Test

Before replacing parts: swap the cylinder 1 coil with another cylinder (cylinder 2 is convenient). Clear codes, drive, and rescan. If the misfire follows the coil (now P0302), the coil is confirmed bad. If P0301 persists, investigate other causes.

Repair Costs

Replacement Philosophy

If the cylinder 1 coil is confirmed bad, you can replace just that coil. However, if the vehicle has significant mileage (60,000+), consider replacing all six coils and plugs as preventive maintenance—they're all the same age.