everyonce in a while when the car has been running and in running temp... the tach would be bouncing from 500-1000.. usualy happen when im stop in a stop light.. now i have new ignition coil(when my old coil melted. lol) new plugs.. new cap and rotor..

 

bump

 

same thing with me. its usually the case of a bad sensor. i replaced my dizzy cause the crank angle sensor (i believe) went bad and caused irratic idleing. its a timing thing when an important sensor like that goes out...throws the timing off cause the ECU won't register what's really going on.

-cody