I have a 91 accord lx 5spd. Ive had the car for 6 months, and ever since i've had it, it seems to hesitate slightly. For instance, if I rev it at idle, it isn't 100% responsive. It hesitates, then revs up. If i shift at anywhere below 3000 rpms, the car is very choppy. only at higher rpms is it smoother, but still not up to par. If I press the gas pedal half way down at lower rpms, the car bucks a little, back and forth. It makes shifting a pain. If i am very gently with the accelerator, i can get it to shift smoothly, but it get to be annoying. The spark plugs and valve cover gasket were changed about 6 months ago. Other than that, I dont know of anything else that is changed. Any ideas on what to check?