What is the procedure to determine a collapsed lifter and how do you replace them on a 83 ford crown Victoria with a 302 fi?

If the lifter has failed, the engine will run poorly due to no valve action on that cyl. Confirmation would be to remove the valve cover to see which valve is not working. You will have to remove the intake to get at the lifter, and if you do that, the might be good to replace them all, hopefully the cam is still good. It is possible that the cam is worn also.That can be replace at the same time thru the front of the engine when you strip it.