RPMs fluctuation no mechanic was able to solve it?

RPMs fluctuation is so weird. No mechanic was able to solve it properly. When I use break in idle position rpm going up continuously. While driving when I use clutch rpm going high. At idle RPMs sometime get stable and sometimes fluctuating at petrol. I have changed throttle senser and then full throttle body in second hand. But the issue is still there. The main problem is that my car rpm is not stable. And sometimes my car getting stop again and again and after sometimes it stays good. Please help me get out of this trauma. Thank you so much.