98 Contour rough Running

My friends 98 Contour is running pretty rough when she starts driving it. Has to give it a lot of gas to keep it going until she reaches about 50MPH and then it seems to clear up, or after 5 minutes or so once the engine warms up it seems to be ok.... shes had regular oil changes... any ideas about this one.... please help!

My Ex had the same problem, same car. Turned out to be a leaking valve cover gasket which was getting into the spark plug ports(?) and soaking ignition wires. check it out! hope it helps.