Hello everyone, I am new here so this is my first post. I am having an issue with a 2011 Aveo where it loses power accelerating and braking/slowing down. The hard part is this is really intermittent. This last happened a few days ago (March 2018, and before that it had happened around 6-8 months ago. Everytime I've taken it in to various auto places and they check it out, can't duplicate it and nothing ever happens and the car naturally runs perfectly. Regardless, this is a very scary issue, as this last time my wife couldn't brake, and the car just coasted to a stop.
It occurred over 3 lights, and the car wasn't responding to the brakes and she states the engine raced briefly. Also, the acceleration was slow, as she had the gas petal all the way down and it was being very slow in responding. She pulled over into a parking lot, turned the car off, waited 10 mins and turned it back on and it ran fine. Over the phone I had her turn the AC off and she was able to drive over 30 mins on the freeway with no issues.

I've combed the internet, and while I see lots of issues for losing power, I haven't seen any that have the braking problem as well.

In a nutshell, there was no engine light, no warning lights at all while this happened. This occurred in warm weather (AZ). The AC was set to the 1 position. The engine raced while braking briefly, and the car was sluggish accelerating but eventually gained enough speed for her to pull over. The brake pedal felt normal, but the car wasn't responding to her presses. The car has no ABS and the car did not die, there was power.

Thank you, any help would be greatly appreciated!