Whole story: my 1995 non-turbo 850 wouldn't start the other day. I replaced my fuel pump and found that it would start up.
But after it started up, its idle was very weak and it shuddered when the throttle is pressed. When in gear and driving, it will drive haltingly for 2 mins then lose power in spite of the gas being pressed.
What is going on? Is this a spark plug/ cylinder issue? Ideas ?
Thanks !

 

Is the Check Engine light on? If so please read the codes first it will narrow the problem(s).

 

You probably should be looking at getting the fuel pressure at the rail tested and possibly a compression test.