Bad CAM follower?

Yes, cam followers, or lifters as they are also known as, can and do go bad. As how to tell this you may have to go to the point of pulling intake and removing them to vissualy inspect them. However, you can try pulling your valve covers off and manually turning motor over-not starting it- and see if any of your rocker arms aren't moving as much as the others. If the rocker arm doesn't compress spring as much on one as it does on another you may have a bad lifter, which I'm sure you know will cause the valve not to open all the way. This leads to weak firing cylinders or missing alltogether. Do you have any tapping or knocking? Backfiring? Be sure all your plugs are firing and your timing is correctly. Hope this helps you out some. Good luck.