I have an edge evo and if my truck idles for a little while I get that alert. In the book it shows it is a cylinder head temp alert. Its winter and I let it warm up and run if I'm coming right back.
Anyone know why this happens and what I should do about it.

 

I'd check the default settings on the tuner. See what the warning is set to for Cylinder Head Temps. Mine get up to 205F tops, and that's during the summer. So there might be something wrong. I'd also check the coolant level as well, just to be on the safe side.

By chance, what's the water temp? Does it match or nearly match the CHT?

 

I have seen mine creep up to 230-235 on a hot day towing a 6000 lbs trailer through the mountains. But at idle, mine always stays down around 200.

I did have a problem with higher than usual readings a while back. Turned out to be a bad thermostat. Changed it and everything was back to normal.

 

Well I checked it out over the last couple days and the coolant temp is running about 192-197. And the cylinder head temp runs about 204-212. This was driving down a 2 lane, about 30 degrees outside. I didn't get to pay much attention in town or get a chance to let it sit and idle.
What temp is the thermostat in an 08 5.4? Where are these temp sensors?

 

It doesn't sound like anything is wrong. Most auto thermostats open around 190-195 degrees, so you're right in that range. Cylinder head temps don't look out of line either.