1986 Ranger 2.0L engine issue

I realize that this vehicle combo really is the opposite of something you'd probably find on these boards, but I figured with the wealth of knowledge here I'd ask in the hope of helping my father-in-law limp along his old beater a little longer.
He has an 86' Ranger with a 2.0L, single barrel carb and a manual trans. The truck only has 76,000 on the clock and was running pretty good just a week or so ago. The truck is basically a basket case, and has been screwed with pretty good by the original owner, but all he uses the truck for is to get around the neighborhood.
The local gas station mechanic told him it had a dead cylinder and was basically scrap. I looked at it and it really doesn't run that bad, and actually idles pretty well. It's just off idle that it'll start to stumble, and lacks power. Get the RPM's up and it'll sing just fine. I tried to do a compression check but my tester doesn't have a long enough reach spark plug hole adapter, so it won't thread in.
All the plugs looked ok, just some black soot, but all are firing. Like I said, it's a basket case, but I've seen newer cars run worse. My gut feeling points to either ignition or timing. Restarts are horrible, and it coughs pretty good during cranking.
Is there any chance this engine might have skipped a tooth on the timing belt? Would doing a basic timing check confirm this?
Any other ideas?

I have not played with these too much but just had an 84 2.3 with a 1bbl carb and after playing with the carb,replaced the EGR valve and all was well again.

These were known for egr problems. Pull the valve and check to plugged passages. I also remember plugged converters when these were new. The one barrel carbs were kow for loose screws causing vacuum leaks between base ans bowl.