Why do this?
servoVal3 = map(servoVal3, 0, 1023,1000, 1750); // scale it to use it with the servo (result between 0 and 180)
servoVal4 = map(servoVal4, 0, 1023, 1250, 1750); // scale it to use it with the servo (result between 70 and 180)
.....
servoVal1 = map(servoVal1, 0, 1023,1000, 1750); // scale it to use it with the servo (result between 0 and 180)
servoVal2 = map(servoVal2, 0, 1023, 1250, 1750); // scale it to use it with the servo (result between 70 and 180)
Don't you want to get values between 0 - 90, and 90 - 180? You need to use IF statements like how I have done. If you don't isolate the values, and use them when you need them, you have problems controlling the robot.