C3 HDI accelerates when changing marches

Hello everyone, my name is Pedro and I'm new to the forum. I'd like to take this opportunity to say hello and thank you for being here.
My question is, I have a Citroen C3 1.4 HDI with 70 hp, and for some time now, when shifting gears up (from 1st to 2nd, for example), when I release the accelerator to shift, I notice the car revs up on its own for a second before returning to its normal engine speed.
I would appreciate any comments, as it's quite annoying in traffic jams and city driving.

Thanks in advance

The most likely cause is that the pedal isn't returning properly, or there's some kind of problem with the TPS, or lastly, excessive wear on the clutch disc.

Thanks, but I don't think it's any of that. The accelerator doesn't fail in neutral; I only tested it while the vehicle was moving, so I think it could be the speed sensor.

Is there anyone out there who can help me, please? Regards

That's why I'm telling you, none of the things I told you to check happen in neutral; they only fail while driving, and when you get to a stop sign or corner and brake, it takes longer than usual to downshift, right? Check this: disconnect the TPS and drive it normally. If it doesn't fail, there's your answer. The Ford has the exact same problem. You've got nothing to lose by trying.