Need Some Guidance

[lexuses drvr]

Hello my fellow Es 300 owners . I recently had my service light appear . I have an aftermarket OBD2 scanner . I pulled scan code po141 ( bank 1 sensor 2 ) air/fuel ratio sensor failure. Well I didn`t buy it from the dealer because of the price. instead i purchased one from sparkplugs.com which sells DENSO brand . I bought the needed one . It came and I began to install . Its weird that I had to remove the drvs.seat to get to the connector because the wire goes through under the body and comes out under the seat . well without me checking . the length of the wire in the new one is shorter than the original one . But the connector is the right one . just shorter . and its not as short as the sensor thats located under the hood on the exhaust manifold . so i know that one is not it either . so what I did was cut & splice the wires . I cut the wires , color matched the wires ( which are the same as the original sensor ) and twisted them together and black taped them secure . I erased the code and started the car . the car is not surging or the rpm`s fluctuating . but the vsc & vsc off light came on . I test drove the car to see how it felt . it feels like the car has no torque . drags to get up tp speed . I`m puzzelled now . don`t know what to do . can anyone tell me whats wrong ? or what I did wrong ? I`m afraid to drive the vehicle like that . anyone please and thanks ahead ...