Hi guys. I've got a problem with my '99 5.4 w/124000. Every once in awhile the truck will run rough when it's idling or shifting into OD. I replaced all of the plugs at about 90,000 when it was really running rough. I got check engine diagnostic codes then, for COPS, but not now. Changing the spark plugs took care of it the last time. I would think I would get a COP code if that was the problem. Any ideas? Thanks.