1996 350 cam and lifter question

I have a 96 2500 4x4 with a 350 . It has developed a lifter noise literally over night.I drove it all day friday with no noise, saturday I got in it to go to work and heard a knocking. I parked it. When I got home I removed the valve cover and started it I found # 5 cylinder exaust rocker was loose. I slowly tightened the rocker nut till it went away and it started to miss. Has anyone heard of lifters going bad (rollers breaking or cam lobe wearing out)? Any help would be appreciated. It has 161,000 miles on it.

I have heard of the lifters starting to click with high mileage but not anything about them going completely out. Are you sure no one has been in there before you tampering with the rocker arms prior to your ownership of the truck? The reason that it started to miss is that the lifter could have had a piece of carbon stuck in it, and by tightening the rocker arm down, you may have dislodged it. You may need to go back in and readjust it. Possibly running a compression check on the motor. Ive got 157000 miles on my 96 z71 5.7L and no signs of major engine malfunction yet. I also am religious of oil changes and only use MOBIL 1 synthetic oil with ACDelco filter PF52. Occasionally I will substitute a quart of oil for a quart of Dexron III to help clean the inside of the motor. Hope this helps. -Chris

SpitAndDirt,

Thanks for the reply.I'm pretty sure no one has been in there before but cant say for sure.We did back the rocker off to where it was the noise stopped for a short time then came back. This thing happened after I parked it for the night. I did get some info from a mechanic friend who said that there has been instances where the needle bearings will come apart and wear the cam down. I too am a fenatic about keeping my oil changed which is why this shocked me. The vin code is R and the option code is L31 Its a C6P truck. My brother in law had a lifter failure in his 7.4 not to long ago,his took out the lobe on his cam.

Tim