1988 Honda Accord INTERMITTENT MISSFIRE OR HICCUP

I REPLACE THE ENGINE WITH A USED JDM ENGINE FROM JAPAN ON THIS 1988 HONDA ACCORED LXI AUTO TRANSMISSION. DROVE IT FOR A WEEK AND NOW I NOTICE THAT THE CAR HAS A MISSFIRE / HICCUPS WHEN IM AT IDLE ONLY BUT DOESNT DO IT WHEN IM DRIVE NOMARL 25-65MPH IDK I REPLACE A BUNCH OF THINGS DISTRIBUTOR ASSEMLY WITH CAP N ROTOR, SPARK PLUGS, IGNITION WIRES, FUEL FILTER, CATAYLITIC CONVERTER, BECAUSE BEFORE THE OIL KEPT GETTING INTO THE EXHAUST SYSTEM BEFORE I FIX THE INTAKE VACCUME HOSES RE-ROATE & NOW I HAVE THIS HEAD ACED PLEASE HELP