Im sure that this question has been answered a million times but I cant find it. my truck has about 105k on it. over the last few months ive had a balance rate on cylinder 8 that was in spec one day out of spec the next. ran the GM upper cylinder cleaner and all balance rates were back to +/-1 in park. now all of a sudden 8 is out of whack again usually around +5, but now #4 & 6 are showing as -4 when cylinder 8 is out. will the other injectors try and compensate for the bad one? The truck does not haze at idle, however it does blow grey smoke, not its usual black.