When driving and rpm reaches 3500 loses speed

Hi everyone, I have an automatic Cavalier 97 2.2 engine and my problem is that, when driving over 40 mph, the car starts having an accelerating failure: revolutions reach and go over 3000 per minute but the vehicle won't develop that speed. I need to reduce the speed until revolutions come back to normal, but again when I want to drive over 40 mph, the false acceleration appears. I've been told the cause of my problem can either be the gearbox or that the injectors are stuck or dirty. When the car loses power or it won't change gears, I need to stop the engine and start it again for it to work properly. Does anyone have an idea what can be happening to my car? Thanks.