Idles Rough on Start Up....

My 98 il SOMETIMES.... mostly after sitting for a day or 2, will start and run rough for 10-15 seconds, caughing and trying to ckear itself up... which it does on its own. Its pretty harsh and hasnt done this in the past. Once its cleared up, its fine and operates normally. Im getting ready to change the fuel and air filters next week. (parts on the way from Auto haus AZ),,,, Spark plugs were done about 2 years ago... mileage on them is not excessive. Any ideas on what might be failing or what might beed attention?
TIA

dealing w the same thing w my 01', rough idle at start and slight coughing at low speed and take off wtf? IDK!!!