WHILE SLOWING FOR A RED LIGHT, PRESSED BRAKE PEDAL AND VEHICLE IMMEDIATELY ACCELERATED BECOMING UNCONTROLLABLE. COLLIDED WITH A PICK UP AHEAD ,WHICH WAS PUSHED INTO A SMALL COMPACT AHEAD OF IT. AIRBAGS DID NOT DEPLOY. HAD EXPERIENCED SLIGHT ACCELERATION ON A PREVIOUS OCCASION, WHICH WAS DISCUSSED WITH MY MECHANIC. ( HAD ALSO HAD THIS PROBLEM ON MY 1999 RANGER WHICH WAS RESOLVED BY REPLACING IAC MOTOR.) VEHICLE CURRENTLY IN DEALERS SHOP, WHERE SERVICE PERSONNEL ARE UNABLE TO REPLICATE OCCURRENCE NOR FIND SOURCE OF PROBLEM. FORD MOTOR COMPANY DISCLAIMS ANY KNOWLEDGE OF PROBLEM ALTHOUGH MANY SEVERAL SIMILAR EVENTS INVOLVING THIS MODEL YEAR ARE WELL DOCUMENTED. VEHICLE IS WELL WITHIN WARRANTY PARAMETERS BUT LITTLE, IF ANY, ACTION IS ONGOING. I AM RELUCTANT TO RESUME OPERATION OF THIS VEHICLE WHILE CONDITION PERSISTS. *TR