missfire an all clylinders,replaced plugs cleaned plenum and ports,no vac leaks on 2002 Acura TL

curious why is TCS light on also? found exhaust leak behind coverter, would that cause a problem with the upper stream 02 senser? or a leak in the valve cover gasget did find abit of oil in that area upon doing plenum. please help thank you so much

Asked by for the 2002 Acura TL