Peugeot 206 1.4 petrol rattling problem

I have been dealing with a rattling problem in my Peugeot 206 x-desing 1.4 gasoline vehicle for about 6 months. There is no problem with the car's traction or operation. There is no misfiring, but I hear a rattling noise when I step on the gas pedal or when the car is loaded while going uphill. Sometimes I also hear this noise when the car is first started. I have changed the catalytic converter, had the valves checked, had the oil serviced and all the heavy maintenance done, but the problem has not been resolved.

It's hard to say without seeing the vehicle, sir. It could be the transmission. It could be the axles. There might be a gap forming in the crankshaft, rod end, and main bearings.