What could it be if it was running perfect. It couldn't be anything if it were running perfect. A flashing light and shaking means a misfire.
Unfortunately for you, my crystal ball has a dead battery so I can't tell you what it is. You'd need someone with a code reader to hook up to your computer and find the codes. Then, you google the code number(s) which will give you a list of all the things you need to check.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.