My wife's DD, a 2004 4.7L HO apparently had a couple of oil pressure drops in the last couple of days - enough to set off the warning. In both cases, it sounds like the engine was at temp, and she was at idle. Both times, more rpms brought it back up. The first time, I checked the level and it was definitely low (slow leak - on my list of things to fix). I'm running organic Rotella 10/30 in it right now. It has ~100K on it, and I've had it for the last 40K.
I did a quick search to see if there was a recurring issue, but didn't find anything. Hoping this is just a bad sensor... any other ideas?