The spark plugs on a 2003 Toyota Sienna are located on the top of the engine, underneath the ignition coils. To access the spark plugs, you will need to remove the engine cover and the ignition coils.
Here are the steps on how to locate the spark plugs on a 2003 Toyota Sienna:
1. Open the hood of your Sienna.
2. Locate the engine cover. It is made of black plastic and is located at the top of the engine.
3. Remove the four 10mm bolts that hold the engine cover in place.
4. Lift the engine cover off of the engine.
5. Locate the ignition coils. They are four cylindrical-shaped components that are connected to the spark plugs.
6. Disconnect the electrical connectors from the ignition coils.
7. Use a 10mm socket and a ratchet to remove the bolts that hold the ignition coils in place.
8. Lift the ignition coils off of the spark plugs.
9. The spark plugs are located underneath the ignition coils.
