Re: How to stop intakebot from moving by itself.
Are you running any code when this happens? If so, would you be willing to post your code (the first part up until the moving by its self might be all that is needed)? Does it happen right away or does it move along a bit and then do it? I don't think this is what you want, but if you want the robot to not move at all no matter what you tell it after (since it won't get there), try this:
And add a motor[motorName] = 0; to it for each of the motors.
As for turning, I would suggest using the gyro. It should be more accurate compared to the encoders since it doesn't depend upon the angle it was facing before the turn (as long as you don't reset the gyro before every turn).
However if you want to use the encoders for making a turn, I am not sure if the 275 is the correct value for a 90° turn, but you can try to find it out by turning x encoder ticks and adjusting the value until it is a 90° turn.