Check the line form the valve cover on the passenger side to the connection up by the heater assembly.

I wish I had pictures, but I do not. The hose is about in the middle of the valve cover and goes up at about a 20 degree angle to the left.

I'll get a picture tomorrow when it is daylight.

 

Oddly enough a 6.0L with a disconnected MAP hose or faulty MAP signal typically will lack power in a big way. The MAP signal is used to control smoke by limiting the fuel quantity during acceleration until a specified boost pressure is obtained. A MAP signal that is detected by the PCM to be out of range or at an incorrect value for specific conditions causes the PCM to ignore the MAP signal and operate the engine from an inferred boost pressure signal. This could explain why your truck still runs decently after driving it some but I have never seen this actually happen. Just sayin. I have left a few of those MAP hoses off over the years and the trucks have no power at all.

The loss of the pressure gage and the P2262 code could be a bad MAP sensor, wiring or a mechanically stuck turbocharger. If you have access to regulated shop air apply 20 PSI to the MAP sensor while monitoring boost pressure on your favorite scan tool and observe the gage on the cluster. If no boost is indicated then you know there is a sensor or electrical concern.

 

Also, you can check the MAP, EBP, and BARO readings at KOEO - should be within 0.5 psi of each other

 

Thanks for the responses. I cleaned the hose for the MAP sensor. It was very dirty. I finally got all of the oil out of the coolant. I realized the easiest way is to let the oil collect in the reservoir then use the shop vac to suck out the oil. Then filled it up with simple green. It is clean as a whistle now.
Again, thanks for all the help.