i HAVE IN THE PAST 4 WEEKS HAD MY CAR SERVICED AND MOT. iT IS A MONDEO GHIA X. Yesterday when I came to a roundabout I stopped to allow the traffic from the right to clear. I held the car as I usually do with the brake. When the traffic had cleared I moved to the accelerator and the car almost stopped then juddered forward. Again today it has done it 4 times. On one occasion it started to roll back then it jumped forward. What is the problem please? and is it a costly repair to sort out? Thanks