It is unlikely your coil is BAD if you are getting good spark to the cap and bad out. It can be a bad/damaged oil or spark plug wire, a defective new rotor, a defective new distributor cap, or even defective plug(s). Unitl you get good spark coming out of cap to the spark plugs, don't waste time and money on anything else. Weak spark will cause hisitation, poor cold starting, poor economy, high emissions, etc.