Black smoke.ihave checked the plugs and i have 4 black ones and 4 white ones

Sounds like you may have and O2 sensor problem . or a fuel delivery problem. Check your fuel presure to make sure it is with in specs I think some where around 55 - 60 lbs running at idle . You will need to have the engine control module scaned to see what codes you may have stored .doing this will lead you in the right direction for a repair , if you have O2 sensor codes start with seeing which ones are working or not . I think there are 4 on your truck 2 on each bank .. bank 1 sensor 1 bank 1 sensor 2 bank 2 sensor 1 bank 2 sensor two . bank one is the side with number 1 cylinder in the firing order the bank 1 sensor 1 or bank 2 sensor 1 are the sensor befor the cat converter and the other sensor are after the cat (pre cat and post cat )