I have this 90 accord for almost 2 years. As it reached its 200k, an engine problem came out, and more frequently lately. After running for a few minutes from cold, the engine hesitates when I step the throttle half-way. It's fine if I only press a little bit, or I step all the way down to the floor, in which case it will gain power suddenly. After a little moment, the problem would be gone.

Anyone can help me with this? Thanks a lot.