Truck sitting

[JimT]

Aside from the engine itself you probably want to inspect anything with rubber, especially with the heat down there. In the same vein all your air lines, fuel lines, coolant lines and wiring warrant inspection for cracks, weather and pest damage. Maybe test the intake for boost leaks. Batteries and connections/grounds probably need a little TLC. Might also want to watch the fuel. Tanks sitting that long, regardless of additives, probably have some amount of moisture or biological buildup. Otherwise a full PM - oil, filters, grease, cabin air filter, etc... - would be the last thing I do before putting it back into service.

One specific thing I've had problems with when my truck sits over the winter months is the HVAC blower and the engine fan clutch. Both have (presumably) built up light rust over the downtime and may get hung up/stuck. Both were easy to remedy when encountered, but it's easier to check ahead of time instead of having to deal with it unexpectedly on the road.

Oh, almost forgot, windshield wiper spray nozzles can collect dust and dirt and may need physical cleaning or replacement. Sometimes it's the little things that go unnoticed until you need them.