Prius intermittently not accelerating

My 2016 Prius has 220,000 miles. Recently moved to AZ. Since temps in 112 degrees car will intermittently not go from a stop position or will not accelerate briefly as though something is not engaging. So far, it will eventually engage and move. Have had it at the dealer twice for diagnostics which comes up with nothing. Learned that the fuel pump on this car is not monitored by the electronic diagnostic system and that the only way to check is for mechanic to be able to recreate the problem and then attach a fuel pump monitor to it. I’m thinking of taking it to a different mechanic. Anyone else has this problem?