The sensors may be slightly off on the voltages they give out. Between .5v-4.5v is normal but lets say the voltages coming from the sensors are slightly higher .7 or so. The computer is getting the voltage correctly but it's interpreting a slightly higher 'normal' voltage as not normal so it tries to counteract it but never can because the highs and lows of the voltages don't match. It can cause problems due to the resistances. Kinda like how I was saying with my coolant temp gauge lol it reads higher than it is but it's normal. The voltages are higher than the computer determines as 'normal' even though the sensor is functioning perfectly.