Control Solenoid and Stepper motors

#1

I am using the XY Plotter kit.

Although I could make it move to certain position as I want.
But one of problem is making solenoid move up and down, while stepper motors are moving.

For instance,
MeDCMotor motor(M1); // Solenoid instead of DC motor.

in Loop, I want Solenoid to do it, But it stops when stepper motors are moving.
motor.run(motorSpeed);
delay(10); // 10,20
motor.stop();
delay(25);

Is it problem of my code? or electric mechanism?

#2