2001 Mazda 323 jerks in car

Have you had your fuel pump replace? How about replacing the fuel fiilter. Car with 160000 miles the problem could be just about anything. It could be dirt or rust in the fuel tank. You could drain the gas tank being very careful with the gas, not to start a fire! See if there is any rust or dirt in the fuel tank. I would think that replacing the fuel pump and filter will correct the problem.