Van missing on acceleration?

I have a Ford e350 v8 year 2002. The van has 126,000 miles. The van had sat for a while and has had some work done to it. New starter, brake lines, bearings replaced in engine, new pan gasket. Mostly on high acceleration a I get bad missing and a shutter like its not getting enough gas or something. I was concerned that it may be the transmission filter clogged, maybe the coils, or maybe the spark plugs need replaced? I'm also getting a speedometer that jumps around part of the time, possibly from sitting. Any serious suggestions or input would be helpful in the diagnosis process. All fluid levels are clean and at max.

Added (1). I did notice a burning smell the one day going up a hill and it was missing/slipping a lot. Really searching for some diagnostic ideas so i can start narrowing it down. I'm afraid to drive it to a shop with it missing like that. Closest shop is 17 miles…

You really need to get the truck to a mechanic. There's almost no chance that you can fix whatever is wrong yourself.