car was giving to me has had new head over one year ago drve car 400+ mies started to have this miss changed plugs,no help.pulled plug wires of running engine from left to right first one made no change in way engine ran but still had fire on plug, next one same thing next two plugs engine did change how it ran .have been told that will tell u if coil is firing??is my coil pack bad or is it my copression,ciol is 180.00 bucks Iwill check conpression next but car will start and run with no problem just very ruff 2-cyls. only my guess??