My 98GT 4.6L started running rough Last Saturday after a 120 mile trip. On Sunday the Check Engine Light came on and although it starts OK it continues to run very rough. The plugs only have a few thousand miles on them, plug wires were not changed. I checked all plug wires to make sure they are seated but now not sure what else to check. Have not drove car since Sunday 9/25. Any suggestions will be appreciated.