did the comp test and no bubbles from radiator.got 170 across all4 cylinders. .i done the oil change and it was straight black..no white film or sludge. some of my co-workers suggested maybe a pinhole in the radiator causing the steam beings the coolant leak may not be enough to see on ground but burn off causing the steam. im replacing radiator, cap, hoses and thermostat friday with all new parts. also a flush with genuine honda antifreeze from the dealer. the hesitation issue might be resolved by a routine tuneup but wouldnt it hesitate all the time instead of just when it gets to operating temp like i explained earlier? if the water pump is bad wouldnt it overheat? how can i tell if its malfunctioning? thanks again for your help.