I'm not sure what's going on with my truck.It is starting to idle rough and the mpg has droped about 2 mpg.I have had a ticking sound for a long time that I thought might be an injecter but I dont have any more smoke than normal and my oli level hasn't changed. so I realy am lost to what is wrong ????

 

Guys i messed up, I put this under 6.7 I was supposed to put in under 5.9. How do i move the thread?