Quote
all three will start off fine then act like they lock up or sit and "sing" and then maybe continue, maybe not.
Does it sound right, like singing starting at a low tone, then raising, just to go low before a stop? Then this sounds like you try to run them too fast. Start slower, like G1 X10 F50.
Esle you might have miswired the motors. Wire colors are unreliable. One of the wires might be broken. Such things.