Need help with 2011 lancer auto problem

Hello everyone, I am new to here,I just experience with this problem my car is 2011 lancer auto, few days ago. I was trying to overtaking a truck on the highway and I did floored it and got stuck at 5000 rpm the RPM does raise but no accelerate even this speed going slower.

And after I am home, I give try to let the car cold down for 20 minutes, and I did give a second try, it's working perfectly from 40km/h achieve to 110km/h in few seconds.

I wondering what happened to my car, ecu or transmission problem. The engine and Transmission Fluids are very clean and the color are gold, this car has been done 71,xxx km
Please help me out, thanks in advance.

You could get the car scanned to see if any fault codes have been stored.

Thank you Frosty7,
I did ask the mechanic to connect to a scanner, but he said that was not thing wrong with it. And then he took me to tast drive up to highway, everything works fine as well ....
He said could be the Ecu problems
So really have no idea what's going on...
But I wonder why scanner can't find the problems, is because need a special scanner for ECU?

It would only throw a code if it was a permanent and persisting problem, but this only seems to happen randomly. Unless you were data logging while it happened you probably wouldn't find anything. Take it to a transmission specialist. Not a mechanic. An actual transmission shop and get them to look at it.