Car stumbles, jerks and hesitates

My car's engine has recently been overhauled. Since then, at when accelerating from idle at first take off the engine stumbles, jerks and hesitates to respond to the accelerator. No one could troubleshoot the problem. Igniter has been cleaned and an ignition cleaner solution was also used, but that did not solve either. All spark plugs have been replaced as well. Still the problem persists. This goes for the several minutes at the first gear and second gear shift and until the engine becomes very hot. I would very much appreciate if anyone has faced similar problem before and the solution came out of this problem.