Dear testdriver though I had cleaned the area and observe no corrosion but now I will remove the plugs and clean the area again.
How we should tighten the plugs, what is the thumb rule? I mean how much force to be applied while tightening the plugs.
Could this be a result of some kind of short circuiting?
Good to hear that you are an ICBian, What marvellous institutions were those. Take care