Mondeo 2004 2.5 Automatic Gearbox Problem! Sos!

[ayybeek]

Recently I bought Mondeo 2004, 2.5 petrol engine, automatic gear box. The problem occuring is this, when accelerated slowly then can reach up to only 80 km/h. But, when push the gas pedal suddenly, the engine revvs and whistles as turbo engine or Ferrari, but the speed does not change, as if you are revving on neutral. Sometimes it speeds up but again very slowly and engines revvs up to 5 to 6 thousand before it shifts, but acceleration is very slow, as if it is towing something huge. I had checked in computer diagnostics - they found that ABS sensor is out of order, so the mechanic said that because of that fault - it is not accelerating as it should. Please tell us about any similar problems, if any occured in the past. thanks a lot. Should I change the sensor or is it gear box fault or anything else?