I recently bought an 89 SpaceCab and all in all it is a great truck, although it does run a bit rough, feels like it could use a tune up. I do not know much about these trucks so I got a couple questions.

It is pretty gutless going up hills, is that common?
Gas mileage is not great, what is the norm for these?

Also found out last night the fourwheel drive does not engage, locked in hubs and tried 4H and 4L both, drive shaft was not even turning. Anyone have any ideas on this?

Thanks