bucking
 

when you mash right down into the truck at a dead stop it runs great pulls hard then it just stops like its running out of fuel. it never did this before i retated the timing and put a new air filter in. any ideas it smokes alot off idle so i dont think its the fuel filter cloged

Why did you retard the timing?

Replace the fuel filter before you spend any money on anything else.

cause i though i had to much timing making the truck idle high