91 honda accord Ruff idle
 

I have a 91 honda accord ex 2dr 2.2. i just replaced the valve cover gasket put new plug and wires on and new fuel filter hopen to solve this problem i have. It doesnt happen all the time it comes and goes. when u pull up to a lite sometimes it acts like it wants to die the rpms will drop below 1 and it will start chunging acten like it wants to die but it only last for a couple of sec. then sometimes when ur driven down the road and u go to get on it a lil it does the same like but at speed. the rpm drop a lil and then a couple of secs it jumps rite back to speed any idea what to do to get rid of this problem?