1998 Ford Fiesta car to keen to pull away

Wife's car,you start the car,1.25 zetec fiesta auto,tick's over about 900rev's you put the car into drive or reverse,and the car wants to go even with you foot hard down on the brakes,the car rises up and down,you take your foot and the car shoots of like a rocket,I just cant solve this problem,?things that I have done,put a new idle control valve on,and new rubber seal,dropped the auto,oil,and put in new up to the right level,warm,and going through the drives,checked for any air leaks,none,checked cables ,ok,put the car into fords for a diagnostic,picked up nothing,they took it for a run,said it drives great,apart from,if you stop and put the car into neutral,and then into drive,and the car rears up,they were of no help at all,any one have any idea's,thanks