Toyota Repair: Toyota echo 2000model, no power down low, o2 sensors, voltage readings

Question
I have carried out tune on vehicle, new plugs, air and fuel filter.  I have chacked fuel pressure. Okay.  The vehicle lacks power at lower RPM.  Checked for fault codes with scan tool.  No codes.  Had a look at O2 Sensors.  One is operation correctly, ighand low voltage readings and the second has low volts at idle and high volts at 2000rpm.  Could it be the catalitic convertor.  Have cleaned throttle body and MAF meter.

Answer
A cat converter failure would turn the check engine light on, I would suggest checking the engine timing, the timing belt may have slipped on the gears, the belt timing can be checked by removing the upper timing cover, the timing marks are on the cam gear, the engine should be at TDC when checking the cam timing.