1.put at least 3 short car sounds (same length)in sprite 1 2.change the green thing in sprite one (details in memo) 3.if you want to change the sounds between the throttle, go to sprite 2 and change the sound 4.change the costume of the car to what u like 5.press the green flag and ur done!
some sounds from here https://scratch.mit.edu/projects/557552680/editor/ i drew the drawing in fire alpaca v2 (can u find the hidden 3 amogus?) gimme things to change the more sounds u have the better it sounds