Ok gang I need run down on two things first the fuse #3 had blown and I also have a check engine light. I was having a rough Idle and hesitation at begining my trips to he store or what ever, I did not have the light when checking the duty cycle, alwas good at 49 to 54%. changed plugs rotor dis. cap and new wires. No change in roughness of idle, then I found that #3 fuse was bad, changed that and it made a great improvement of idle. my question is WHY!