[cobrashoch]

May be (and most likly is) a flat cam lobe. BUT, it could be a bent/or bad pushrod, a bad rocker, or other valve drive train issues such as a broken spring, in addition to the other stuff listed above. Hard to call from far away, so find s good mechanic. All of this stuff is fairly easy to fix when you find the right problem. Don't forget to think about what might have caused the problem in the first place. It could set off a chain of other fixit problems. Good luck, cobrashock