You need only have your car scanned for any and all codes and get them relayed to me as then we can elminate , and evaluate the source of failure.
It sounds as though a sensor failure has occured and has been overlooked.
The reason I,v asked you to have your Toyota scanned is if you have already changed the spark plugs and wires and your car still jerking and sputtering any of the Numerous Engine Management sensors may have failed,
You see these sensors take readings of air flow, tempature,vacume ,Throttle position, EXT... to many sensors to mention ( in the area of 15) to relay Information back to your compoter so it may correct air /fuel mixtures , timing all the things your car need`s to run properly, so short of replacing these sensors needlessy , the scanner will guide you in the direction (and sometimes even pinpoint and tell you) what sensor has failed to create your problem. most common failed in your case would be;Fuel Injector`s , Mass Air flow sensor ,E.G.R. sensor, O/2 sensor`s camshaft sensor.