I realize this... I really dont understand how the Ecu can NOT be throwing a code. i KNOW it is not normal for a a/f guage just lean out and never ever come up (the thing just stays black). I realize this is a fairly useless guage but being that it isnt working properly indicates a problem since the guage is wired directly off the o2 sensor signal wire going into the ecu.. Also the jerking of the car during medium engine load is just not right ..