2003 F250 7.3
Scangauge says LP (fuel system loop status) is open even after driving awhile. Everything I've read says it should be closed after warm up?

Oxygen sensor?

I've also noticed I don't seem to get the raised idle after extended idle periods anymore. Related problem?

 

Fuel system status will always be open loop on the 7.3 engine.
Closed loop generally refers to the point where a sensor is brought online in order to measure the effect of a solenoid or regulator. In the case of a gasoline engine, the computer estimates the fuel ratio until the oxygen sensor has warmed up enough to function properly. At that point the fuel mixture data is used to calculate fuel trim and continues in a constant cycle.

For the 7.3 engine, a good example of a closed loop system is the PCM-IPR-ICP. Unpluging the ICP puts that system in open loop status.