Tip - Bad Ignition Coil Symptoms | eHow

A bad coil can cause the engine to idle and run rough. It might feel weak with a tendency to stall, and may start to backfire. When the coil fails completely it will cause a non-running condition, or in the case of a coil-over-plug application, a dead miss in that particular cylinder. Bucking may accompany backfiring when the car's in gear, similar...