Update: 1999 Honda Civic EX P0300,P0301,P0303,P1399 Misfire Prob

Changed all 4 spark plugs -- old ones seem not bad anyway. Rechecked plug wire set connection but did not change. Now it starts normally, seems ok whe accelerating with slightly noisier than before. But engine still shake slightly and idling speed fluctuate a bit once in a hile when idling -- seems still having misfire isssue. Asked a friend who do car repairing work and was sugeested to replace distributor cap/cover to see if this can solve the issue, otherwise may need  to replace the plug wireset (purchased new set but have not changed yet).