Possible Causes

WARNING: This page is about a different car, the 2003 Mazda B4000, 2003 Mazda B3000, and 2003 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.

Possible causes are:

Coil driver circuit shorted to ground.
Coil driver circuit shorted to VPWR.
Damaged coil.
Open or short in ignition START/RUN circuit.
Open coil driver circuit.