The firing order for the 2003 Toyota Tacoma with the 3.4L V6 (5VZ-FE) is 1-4-2-5-3-6. This article explains what that means and how to verify it, along with practical notes for maintenance and diagnostics.
The 5VZ-FE engine in this truck is a dual overhead cam V6 that uses coil-on-plug ignition. Understanding the firing order helps with spark plug replacement, ignition coil testing, and timing-related maintenance. In Toyota's cylinder numbering, cylinders 1-3-5 are on one bank and 2-4-6 are on the opposite bank; the front-most cylinder on a bank is numbered 1, with the sequence continuing along that bank.
Ignition sequence for the 3.4L V6 (5VZ-FE)
Below is the sequence in which the spark plugs fire for the engine, based on the standard cylinder numbering used by Toyota for this family of V6 engines.
- 1
- 4
- 2
- 5
- 3
- 6
Note: The numbers reflect the engine’s cylinder numbering as described above. Always refer to the official service manual for exact mapping to your vehicle’s ignition coils and spark plugs.
Notes and verification
For DIY maintenance and diagnostics, remember that the 3.4L V6 in the 2003 Tacoma uses three coil-on-plug assemblies. The firing order itself does not change, but coils must be connected to the correct cylinders. When performing timing work, timing belt/chain checks, or spark plug replacements, disable the ignition system and rotate the engine only with the crankshaft pulley bolt. If you’re unsure about cylinder mapping, consult the Toyota service manual or a dealership technician.
Summary
In a 2003 Toyota Tacoma equipped with the 3.4L V6 (5VZ-FE), the firing order is 1-4-2-5-3-6. Cylinders are numbered with 1-3-5 on one bank and 2-4-6 on the other. Always verify with the factory service manual and follow proper safety procedures during ignition or timing work.