I don't own the truck yet I'm tryin to figure out of I can fix orient not b4 I take the plunge

 

Simple things then

Check the LP pressure. You might have to spend $$ for a gauge and fittings but they work for a lot of things.

Check the oil for fuel in it. Tip off for injector problems.

What color smoke when it starts smoking and dies? Thats a big tip off for wher ethe problem is.

When it is idling do you hear any misses of really loud knocks\rattles?