1991 Honda Civic Can't figure out the problem

Engine Performance problem
1991 Honda Civic 6 cyl Front Wheel Drive Manual 200k miles

I had a major oil leak and they recently fixed that. I have also replaced the timing belt, spark plugs, not the wires yet, water pump and some kind of seals.

When I am going down the road, I can be in 2nd, 3rd, or 4th gear and my car will jerk me back as if I were in a really high gear, but I am not. It sounds like it's cutting out, but it stops immediately. Then 5 minutes later it does it again. It only does it when the engine is warm. Also, when I stop, my engine revs up and down constantly, again, only after it's hot. It doesn't rev really high, but it goes up and almost down too low. I did have them reset the rpm's and it's still doing it.

Does anyone have any idea what I should do next? I am changing the spk. Plug wires tomorrow!

Thanks, Courtney