Hello, what could cause a new automatic transmission car to accelerate by itself while driving at highway speeds on hwy. I did have to brake, but before I did, the car leapt forward and gained speed very rapidly even though I had immediately removed my foot completely from the gas pedal. It was a slight downhill, but I did not expect the engine to rev, as if the gears shot up into a high gear, shooting the car forward so quickly.
Your car is under warranty.Take it to the dealer
Was this in a downhill? Maybe it has little engine braking, compared to your previous car. Or maybe it has adaptive cruise control and it was accelerating back to the set speed. If neither, take it to the dealer.
Were you using cruise control? Was your finger on the “+” button? The new Mazdas will jump the cruise setting up in 5mph increments if you press and hold the “+” button. I discovered this on my 2018 when my car took off (on the way to 90mph) until I tapped the brake and realized what had happened. My previous Mazda only increased the setting 1 mph at a time while holding the button down.