HI, ANY THOUGHTS ON WHY MY SPEEDO NEEDLE BOUNCES UP AND DOWN WHEN DRIVING

. WAS DRIVING HOME FROM WORK DOING 60 (ACCORDIN TO TOMTOM) AND THE NEEDLES JUMPING BETWEEN 55 AND 65 MPH. ALSO, CAN ANY1 TELL ME A GOOD PLACE TO BUY RS2000 SIDE SKIRTS AND REAR SPRATS FOR MY CAR. MUST BE GENUINE FORD PARTS AND CHEAP IF POSS. KENT CAMS SOON....
MANY THANKS FOR ANY ADVICE
