wierd sound please help

I have a 96 honda accord lx, non-vtec. Ive noticed this for alittle while
now, heres the prob. When im driving at slow speed and ill tap on the gas
padel then let go. It seems like something in the engine still spins then
stops. Sometimes it does it for little longer then the other time. Wierd but
it does it around 20 mph. Sounds like somethings still rattling or clicking
then stops please help! But i dont notice it in neutral, could someone
explain?