ok so i have a 83 chevy blazer it has a 350 in it with a carb, and distributer. i put in a autometer tachometer gauge that reads by having a positive wire that goes to the positive post on teh coil. somthimes the engine will start to sputter badly, when this happens the gauge needle reads all over the place. what could the problem be? it happens randomly and will sometimes be bad enough to make the engine stop. im thinking it has to do with the rotor and cap or coil or spark plugs or points. i pulled two of the plugs out, one from each side and both looked normal, a little tan on the tips. im not thinking it is the engine not getting enough gas because the tach needle dosnt read smooth at it dies, instaed it is all over the place as if it is missing sparks. since the tach is connected to the positive wire on the coil not the spark plug wire on the coil am i right to think it is somthing before the coil that is wrong like the points? i dont really understand how the points work either. i also checked the cap and there was a lot of biuldup on the contacts so i dremeled them cleen along with the cap. could the dremeling have made the gap between the contacts too big?