1991 Honda Accord Engine stumbling during acceleration

Engine Performance problem
1991 Honda Accord Manual 205000 miles

I have a '91 Accord that has recently had problems with acceleration. When the car is first started, acceleration is fine. However, once the car is warmed up, the engine does not accelerate like it used to. Instead, I have to very slowly accelerate; normal acceleration results in vibrations and what feels like a flooded engine. Searching on the net indicates that this problem is best described as "stumbling" and the information on this symptom seems to vary rather widely. Any tips?