I've replaced 16 valve seals, oil pump, water pump and timing kit on my 2005 Aveo and now I have a rough idle and no error codes . When this condition occurs, I see in my Innova OBD2 scanner an incorrect STFT and LTFT value, this values are negative, almost -20%. A rough idle disappear when disconnect the oxygen sensor from the exhaust manifold. I’ve tested my ECM and O2S in other Aveo and it's fine.
What is the reason for this condition?
