Toyota Vitz 99 problems

Hello everyone.
I am new in this. 3 weeks ago I was refined to the engine of my Toyota Vitz 99 (automatic transmission). The mechanic disconnected the battery to shine the vehicle. When picking it up from the workshop, I noticed that it lost strength and that it took to make the changes in the speeds.
A friend told me to put injector cleaner (Fuel injector Cleaner) the next day my car recovered the power and speed change was normal.

Three days ago I took my drums to spark my dad's car, after a few minutes, connected my battery to the car and noticed that I had again lost power and again problems with speed changes.

Does it have something to disconnect the battery? What can I do?
Someone who guides me.

A hug

Hello partner, when you disconnect the battery, the ECU is deprogram and then you must learn the characteristics of the engine again, drive it for one hour varying all the regimes until it returns to normal, sorted and out.

It is true what Jal says, but you can do it by reprogramming with a scanner, what I did not understand is because I disconnect the battery the mechanic to perform a scanner, the scanner are made with the open contact you do not have to take the battery.

Companion:
Thank you for your advice, I will put them into practice.

A hug

Kikemec:

I also thank you and you left me a great doubt in terms of my mechanic disconnected the battery to scan.

Thanks and a hug