i have been having problems with layer shifting on my tevo tornado lately. i tried fixing it by lowering the voltage on the stepper motor to .99 volts. this helped a little but the shifting is still apparent problem. someone on the tevo tornado thingiverse group suggested that i set the acceleration to 3000 so i set it to 3000 and saved the settings. the problem with this is that when i start a print it changes the acceleration to 500, but sometimes in the menu it flickers between 5000 and 500. is there somthing i can do about these problems, or do i just have a bad unit?