Problems with acceleration 2002 prius

I have a 2002 Prius, and no error codes or warning lights on. About over 6 months ago my car started showing the triangle of death and the symbol of the car with an exclamation mark in it. When I tried to read the code with a scanner it showed no error codes. And the symbol kept going away for a few days and would come back for a day or two until it just disappeared and never came back. Each time it came back it never showed any error codes, and the car didn’t seem to be making any weird noises or driving different. Today I was driving and at a red light. When I started accelerating my car kept skipping and going in and out of accelerating. It’s never done this before and seemed fine after that until I drove over 50 mph then it would sound like it was struggling to accelerate and the fans in the back would start sounding really loud. Any clues what this can be??