2008 350 Super Duty 6.4 Diesel, its blowing blue smoke and knocking from engine on 2008 Ford F-350 Super Duty

i just got this about 1 month ago seams that it smokes more often. not sure if its do to the weather also loosing fuel comsoption. the knockin from the engine getting little louder also. someone told me the injectors are the problem. however not sure anyone can help me with this? i do have warranty on the vehicle, will this be covered or should it be?

Asked by for the 2008 Ford F-350 Super Duty
Might want to read your warranty coverage at this time.Don't drive it anymore , until you find out what's covered , to avoid damage that may not be covered. IF you don't understand the wording in the warranty papers please don't hesitate to find someone you know that can help you!!! No sense in paying for something if don't have to! IF it's not covered , find a QUALIFIED DIESEL mechanic , don't guess!!!!!!!!!