i also had the same problem with my 88 hf...i pretty much thought it was the 02 sensor causing the hesitation...it only happened when i was trying to hold speed and not when i was decelerating or when moderately accelerating

another theory i had was clutch chatter...the car would shake a little under acceleration from the start (had to give it lots of gas to get it moving)

i never fixed it b/c i was doing a swap...i put in a rebuilt d16a6...so basically this isn't much help