02ls400

in my recent threat i had talk about how my car(2000 ls 400) was giving fault codes and problems. So I just bought a used ecu from ebay, and i had locksmith reflash it. after he flash it he plug it in the car still wouldn't turn over the. but i have been reading the lexus forums and i feel i have all the symptoms of a bad ecu. poor acceleration rough idle/engine, glitchy odometer, reverse mirrors not working, bad gear transitions, and poor mpg. what is my next best step. because im on the urge of selling this car