The VQ40DE wants NGK Laser Iridium DILFR5A11, gapped from the factory at 0.043 inches, torqued to 18 ft-lbs. Replace at 105,000 miles. Do not pre-gap — checking with a feeler gauge is fine, but bending the ground electrode on an iridium plug ruins the precious-metal tip.
The VQ40DE puts the rear three plugs against the firewall, which is the only part of this job that earns its difficulty rating. Pull the air intake assembly and the coolant overflow tank, and you'll see four of the six plugs without contortion. The rear three on the passenger side and the rearmost on the driver side need a swivel adapter and patience. Budget 90 minutes the first time, 45 minutes once you've done it.
VG33E (R50) is friendlier — the plugs sit under the upper intake plenum on some years, accessible without major teardown on the rest. Confirm your year before ordering: 1996–2000 R50s use the older PFR5G-11 platinum; later R50s moved to the iridium-tipped replacement. The torque spec on the aluminum head is 18 ft-lbs regardless of generation. Going past 22 ft-lbs is how you crack a plug well or strip the threads in an aluminum head.
Apply anti-seize sparingly — a smear on the threads, none on the seat. NGK officially says no anti-seize because their plating handles galling on its own, but in the desert with dissimilar metals, a light film prevents the seizure that ruins your next plug change. If you anti-seize, back the torque off about 10%: aim for 16 ft-lbs instead of 18.
Coil boots crack from heat cycling. If you're already in there, pull each coil and look at the rubber boot — any visible cracking means it's a misfire waiting to happen. Z1 Off-Road sells replacement boots for under $20 each. Cheaper than chasing a P030X code six months from now.
| Part | Vendor | Est. price |
|---|---|---|
| NGK Laser Iridium DILFR5A11 (VQ40DE, 2008+) | NGK | ~$14 |
| NGK Laser Platinum PLFR5A-11 (VQ40DE 2005-2007) | NGK | ~$12 |
| NGK PFR5G-11 (VG33E) | NGK | ~$12 |
| OEM coil boots (replace if cracked) | Nissan | ~$18 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.