Spark Plug Replacement — 4.0L V6 and 3.5L V6
The 4.0L (1GR-FE) and 3.5L (2GR-FKS) both take six iridium plugs with a 100K mile interval. Rear bank plugs require intake plenum removal — plan 2+ hours your first time. Torque is 13 ft-lb on both engines, gap pre-set at 0.043". Use Denso or NGK iridium; do not regap.
The Tacoma's V6 engines share the same fundamental layout: coil-on-plug with the front three plugs accessible from the top of the engine and the rear three buried under the intake plenum. This is the part most owners aren't ready for — pulling the intake adds an hour, requires removing several vacuum and electrical connectors, and demands attention to the new intake gaskets on reassembly.
Plug choice. The 1GR-FE OE plug is Denso SK20HR11 (NGK IFR6T11 is the equivalent). 2GR-FKS uses Denso FK20HBR11 or NGK ILZKR7B11. All are iridium long-life, factory-gapped at 0.043", and last 100,000 miles. Don't regap iridium — the precious metal tip is thin and chips when bent. Don't use copper plugs as a "cheap alternative" on these engines; the coil-on-plug system is tuned for the higher resistance of iridium and copper causes misfires under load.
Front bank. Front three plugs are visible after removing the engine cover. Pull each coil's 10mm bolt, disconnect the harness clip, and lift the coil out. Plug socket goes straight down.
Rear bank. Rear three sit between the intake plenum and the firewall. You have to remove the plenum to reach them. This means:
- Disconnect throttle body harness and unbolt the throttle body (4 bolts)
- Disconnect EVAP, PCV, and brake booster vacuum lines
- Unbolt the plenum (10mm bolts, sequence matters on reassembly)
- Lift the plenum up and aside, leaving fuel lines connected
- Cover the open intake runners with shop rags so nothing falls in
On reassembly, replace the intake plenum gasket (one piece, reusable in theory, but cheap enough to replace at 100K).
Torque is small. 13 ft-lb is hand-tight plus a quarter turn. The aluminum head will pull threads if you torque this from memory. Use a small in-lb wrench (156 in-lb = 13 ft-lb).
Steps
- Engine cold. Disconnect negative battery cable.
- Pull engine cover (friction fit on 4 grommets).
- Front bank (3 plugs): Disconnect each coil connector. Remove 10mm coil bolt. Pull coil straight up. Blow compressed air into the plug well to clear debris.
- Back the old plug out a half turn with the 14mm thin-wall plug socket and 6" extension. Then turn by hand to feel for cross-threading or stuck threads.
- Inspect the old plug — even wear and tan color = good. Erosion = past life or wrong heat range.
- Verify the new plug's gap with a wire gauge (don't bend). Apply dielectric grease inside the coil boot.
- Thread new plug by hand. If it doesn't go in by hand, stop. Torque to 13 ft-lb (156 in-lb).
- Reinstall coil, torque 10mm bolt to 60 in-lb (5 ft-lb). Reconnect harness.
- Rear bank (3 plugs): Remove throttle body (4 bolts), set aside without disconnecting cooling lines if possible.
- Disconnect PCV, EVAP, and brake booster vacuum hoses from the plenum.
- Loosen and remove plenum bolts in reverse of torque sequence (consult service manual).
- Lift plenum up and toward firewall. Stuff clean rags into the intake runners.
- Repeat plug replacement procedure for rear three.
- Remove rags. Install new intake plenum gasket. Reinstall plenum, torque bolts in correct sequence (typically center-out, multiple passes).
- Reconnect all vacuum lines, throttle body, harnesses. Reconnect battery.
- Start, listen for misfire, scan for codes if you have a reader.
Why it works
- 100K mile interval — long service life
- Iridium plugs run cleaner than copper on these engines
- Front three are quick (15 min)
- One job for the next decade on most owners
Trade-offs
- Rear three require intake plenum removal (2+ hours)
- Intake plenum gasket replacement is recommended (extra $25)
- Aluminum heads punish overtorque
- DIY mistake on the rear bank can damage the intake gasket or drop a bolt into a runner
Tools required
- 10mm socket
- 14mm thin-wall spark plug socket
- 3/8" ratchet and extensions (6" and 10")
- torque wrench (in-lb capable)
- dielectric grease
- compressed air or shop vac
Parts
| Part | Vendor | Est. price |
|---|---|---|
| Denso SK20HR11 iridium long-life (1GR-FE, qty 6) | Denso | ~$65 |
| Denso FK20HBR11 iridium (2GR-FKS, qty 6) | Denso | ~$85 |
| NGK ILZKR7B11 (alt 2GR-FKS, qty 6) | NGK | ~$70 |
Sources
- Toyota Tacoma service info — 100K mi plug interval, 13 ft-lb torque
- Denso SK20HR11 OE spec for Toyota 4.0L V6
- Tacoma World: rear bank intake plenum removal walkthrough
Related
- Spark Plug Service — 4-Cylinder and V6, and Why You Don't Wait Too Long
- Oil Change — 1GR-FE 4.0L and 2GR-FKS 3.5L
- All Toyota Tacoma guides & tools
- Browse the full DIY database
Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.