Okey will do, checked today all o2 sensors on computer, and i didnt get a voltage on one of the sensors bank 1 sensor 2 thats seems like after cat sensor. I did got the engine management light before but deleted it ages ago and never appeared again. It came because i had a big hole before the cat, i think. Should i replace o2 sensor after cat? does it do anything to make emmisions change? I thought only the precat sensor does the job, the other one just measures the oxygen?