Engine "missing out" between 40-55 mph

[JHALL]

The term "missing out" is the best I could describe the issue. It feels like a "miss" on a gas engine. At 40-55 mph under a load (lugging up a hill, etc) it will "miss out" until you get above about 55-60 mph or until you accelerate harder.

The problem does not occur driving around town or at idle or when driving 70-80mph down the highway. It is only under a load between 40-55mph and it is intermittent, it doesn't happen every time.

I first noticed the issue after returning from a road trip to Tennessee and back which the truck did flawlessly. I dropped my girlfriend off and started on my way home. I had to slam on my brakes to avoid a deer and when I went to re-accelerate is when I noticed the problem.

The check engine light is not on. The truck has 263,000 miles.

Ideas?

[JHALL]

Anyone have any ideas?

[JHALL]

4 or 5 years ago, the truck had a similar issue, where it would "buck" really hard on the highway and would die when pulling up to a stop when it was raining. The current issue does not "buck" near as hard like it would with the previous issue nor does rain change the nature of the problem.

The previous issue turned out to be the CPS. Does anyone think that could be the issue, or could I have bigger problems ahead of me (ICP, injector wire harness, injector, etc).

What's throwing me off is that it is intermittent, but consistent enough to have me concerned.