207 goes at its own constant speed in each gear

hello everyone 207 2009 model diesel 1.6 hybrid model car 1 2 3 4 5 it does not matter as soon as you put it in gear, the car is going at a certain speed according to its own gear height, it is like auto, it is like speed stabilization, I am waiting for your comments. thanks

I say air flow meter and solenoid valve control. one should connect the vehicle to the pc and look at the error code

So is there any tapping on the tachometer, or for example the tachometer shows when in 4th gear and in 5th gear

When I was buying the vehicle, he changed the flow meter to be defective, he gave me the old one, he changed it, and he gave me an old flow meter.

I think it seems to me that there is no abnormality in a normal situation.