Time to pay the piper?

My truck is beyond the 7 year, 200000 mile injector warranty allowed by GM (in service 10/02) and it has been a sweet baby so far! I love it! ...At 113K I'm starting to notice escessive blue smoke and a slight reduction in my fuel economy. I watch it pretty close. I am guessing one or more injectors are getting iffy. I do a lot of camper & boat hauling between TN to AL coast. I need to understand how injectors fail out and will they likely shut me down on the highway if one fails completely? Is it time to just bite the bullet and replace all injectors? I'm not a serious mechanic so its gonna be a big tab item for me!

Any advice welcomed! Boat hauling/fishing season starts next month!

:help