load vibrating noise potterton suprima ?

I have had a problem with my boiler and boiler mate the first was a senser on the boiler mate and was easily traced . 4 weeks later i am geting a very load vibrating noise when the boiler starts or sometimes comes and goes when it is running . if you move the small multi plug with the red and black leads (i thinkits the gas valve leads ) it stops . not sure if its the valve or the board ? .