Caution: Due to the high voltage generated by the ignition system, caution must be taken when performing any work on ignition system components.
Perform a general check of the ignition system as follows:
If the engine turns over with the starter but does not start, disconnect the high-tension wire from any spark plug and connect it to an additional good spark plug whose housing is securely fastened to the engine.
Relieve pressure in the fuel system. When checking the ignition system, do not connect the fuel pump electrical connector.
Turn the crankshaft and carefully look at the interelectrode gap of the additional spark plug. Bright blue sparks should flash periodically in it.
If sparking occurs, remove and reconnect the high-voltage wires to the test spark plug one by one. The presence of sparking on each high-voltage wire indicates that the ignition coils are working properly. However, the spark plugs themselves may be dirty, so remove and clean them or replace them with new ones.
If there is no spark or it is very erratic, check the voltage supply circuits to the ignition coils and the resistance of the ignition coil windings, as well as the condition and resistance of each high-voltage wire.
This material is taken from a resource (TOYOTAMAN)
If all components and electrical circuits tested are good on 1996 to 1997 models, the ignition coil may be faulty, and on 1998 and later models, the camshaft position sensor and/or crankshaft angle sensor may be faulty.