avbad12

i have a 1976 datsun 280z and it runs ok until it heats up and then starts sputtering and running like $hit! when i stop at a red light, the rpms hover from 500-1000 and eventually the thing shuts off. When i start it again after that i have to give it a ton of gas and then alot of smoke comes out the back. i have replaced the cold start injector and temp sensor and i attempted to replace the mass airflow sensor today but it ran even worse. any ideas? and does the mass airflow sensor need adjusting right out of the box?