When I press the accelerator on my nissan sunny 1.4L (auto 1994) the car does not move from a stationary position even though i can see the rev counter and hear the engine reving up.It will start moving very slowly after 3 or 4 attemps at pressing the throttle and this sometimes cause the car to switch off. once the car has picked up speed, I can drive it and feel the gears changing normally. The problem starts again if I break or stop at a junction or bring the car to rest.There is no problems with starting the car or any misfiring. Any suggestions or help would be much appreciated