2006 Renault Clio Hi Desprate M Driving Renalt 3 Had Main Bigend Bearings

Hi I am desprate for help. I'm driving a Renalt Clio 3 had the main and bigend bearings replaced. Since then my car missfire, but when I turn the ignition switch on and off while driving the car will start running smooth. Had plugs, coils, Lambda sensor replace but still no cure. Even the mechanic does not know anymore. Any suggestions please