On a 2006 kia sorento i have 3 O2 sensors how do i no witch one is bad

No, you have 4 sensors. One "pre-cat" oxygen sensor, one "post cat" oxygen sensor for each "bank" of the engine. Two banks. So, there are 4 sensors. Why do you think an oxygen sensor is "bad" causing no power climbing? What else can you share about your vehicle? Diagnostic testing desperately needs to be performed by a qualified technician with proper resources and tooling. www.repairpal.com/repair-shops Try that link to find a shop near you to communicate with locally.