93 LX, no spark, replaced ECM, MAP, Engine temp Sensor, plugs and distributor. Still no spark. The Tach needle bounces around at 3K rpm and above. New ECM no codes. Ignition relay tested good. ignition switch is worn, key will come out in any position. . Also 285K milage and #4 is down to 90 Psi dry and 145 wet. Anybody have a clue? I don't.