Some ECU's Are DUMB And They Don't Show CEL Sometimes Even When Sensor Goes BAD....
Don't Know What's That But It Happens Sometimes......If It Was Me...I Would Have Check Each And Every Sensor One By One To Make Sure Everything Is In Perfect Working Condition....
But 1st Check All Other Major Things ....!!
Also Do Tell What DO You Mean By Not Performing Well???? Its Restricting??? Missing On Petrol.....Or What