No gas cut at the bipper shift

I just joined you. I was not aware of the existence of such a forum. I noticed when I was researching the failure of my vehicle. I got very useful information.

I couldn't find information about my problem. I'll be happy if you can help me.

I have a 2009 model Bipper. I bought my car zero. After 15-20 km after exhaust inspection with 12000 maintenance, the gas is cut slowly in gear changes. (Tachometer normal) My vehicle makes a forward attack if I change speed. No problem if I change it slowly.

I have had all the maintenance done in the service so far, as it is guaranteed. Although I take it to the service every month, they said there is no such problem in your vehicle. I suspect the vehicle has a problem with its brain.

Thanks for your help in advance.