94 4.0 awd starting problem

Hello All; I am new here. I am having a strange problem with my old areostar. It has 217K on it and the other day it wouldnt start. It almost does but skips like it is out of time. It has been running rough for about 4 miles but suddenly would run great. Everyone thinks it want to die but maybe there is a sensor or something. It has been a great car. I did change the engine computer. Thanks