Mine did exactly the same as wot your sayin like a judder though the pedals. Can you feel it though the steering wheel as well? If so i would bet it the tolerance bush in the steering coloum is fooked. You can get these from ford it a small bearing and a plastic bush (about £4) and it fits behind the steering wheel. I changed all the bushs,steering rack,T.C.As,track rod ends and all the engine and gearbox mounts and it turned out to be this