I have 82 Supra that cranks good. There is spark at the ignition coil. Tested injector pulse with noid light, and it checked out good. Fuel pump working and pressure is good. However, when I checked the spark at the spark plug wires, there is no spark or sometimes spark. I pulled plug wires off distributor cap and tested spark with check light, and there is no spark. Is it the pickup coil? or distributor cap/rotor? plug wires? Any advise will be appreciated.