Valvetrain rattling excessively after driving for a while

[RangerReviver1990]

I've already seen and looked at all the 4.0 ticking forums before I made another one but I kinda need a specific answer. So up until recently my '90 4.0 has had the ticking on cold starts and it usually goes away after I let it idle for a bit before I drive, mainly because I leave right off of a highway and don't want to overstress my engine everyday, if that makes sense. But recently, I've had to either let it sit longer or have to drive through my neighborhood with a engine that sounds like a Powerstroke clacking away like it's nobody's business, but as soon as that needle starts moving it dies down and straight up stops. But I first noticed it a couple weeks ago when it was well up to operating temperature and was just driving around for a good hour and a half without problems down some dirt paths but when I got onto the main road and gave it some gas, I thought I broke something because the ticking gradually came back and was kind of in the background intermittently. Almost like one lifter was ticking, then a couple more, then it'd stop, and repeat. But today I went to work for a hour or two, and just drove around town and turned my truck off and let it sit for about half an hour and then I started it back up again to go home and when I started getting up to highway speeds, the ticking came back so I pulled off the side of road and it apparently made it worse because the Powerstroke-like noise came back and would not go away until I shut the truck off. My thing is, nothing is loose. My dad and I check the valvetrain top to bottom a couple months ago and since I don't drive it that much, it doesn't really make sense that the engine would degrade so rapidly within 1500 or so.

 

[Curious Hound]

I would recommend checking your oil pressure and make sure the oil level is good.

 

[avid]

When you checked the valvetrain did you check to make sure oil was able to get up through to the rockers via those three bolts that hold the shaft in place? You can see what I'm talking about in this dude's video:

Also, the rocker arms need to be adjusted just right or they can block the flow of oil. He shows that in the first 5 minutes of this viedo: