2002 Pontiac Grand Prix electrical problems maybe

I have a 2002 Grand Prix GTP. while I'm driving my RPM meter goes to 0 and TCS turns off but the car will still be running. That's how it started I thought it was nothing. but now sometimes it will do that and my car will just stop while I'm driving but the lights and music will still be on so I didn't think it was the battery. it's getting worse. some people said I just needed a tune up. and I called a mechanic and he said since its a GM car it might be the clutch sensor.