how can you tell a tps problem from a real trans problem? I have 88 with auto. when driving on the frwy. at about 55 to 60 mph. I will let of the throttle a little to slow down. then when I apply the throttle again the engine will just rev as if its in neutral. if I let the vehicle slow down to about 35 mph. it will get back into gear and pick up speed again. anyone had this sympton before?