how can i fix a misfire on a rover 216se?

my coupe misfires when idleing and when you accelerate hard ,if you build up the revs slowly its fine ive checked the plugs,distributor and rotor arm and all seem ok it also has alot of trouble starting first thing but any time after that for the rest of the day it starts straight away i have run out of ideas if any one can offer advise i would be gratefull