1996grandprix 
so, i got the car home and well it runs. not very well but it does. its knocking but not very loud. (like piston slap i know these will do that to) and its smoking very badly (en off to make me shut the car off and had the fire department called) so would it be worth it to rebuild the engine? i priced everything out and its only 250$ to do. i want this engine to last a long time if i do rebuild it because im going to school full time and working a job after words. i am already kind of out of my budget by fixing this car (only working 1 day a week) but i need this car fixed as soon as possible for work (cant relay on people for rides anymore and cant afford a new car or cant lease one because im under age...). another issue im having is the check engine light came on ( random misfire and both o2 censers) i know the misfire is there but the o2 censers did not have a problem before this engine problem happen so what could the problem be?? (bad o2 censers??)
sorry for throwing all these problems at you but you seem like you know what your talking about with these engines.
