I've started using Howes. The lie o meter is running 0.5 more now but I'll run through the bottle for a few tanks and see if it's just me wishing for more mpg.I have used Howes diesel additive for 35 yrs. In my semis and pickups . Unlike gas, diesel is a single source product . Meaning you will get the same diesel within a given area by one supplier . Not Shell diesel or Chevron diesel just diesel. Additives to diesel are worthwhile investments. Especially with Bio fuel that has a lower pour point ( meaning it will jell up at a higher ambient temp) Also helps with lubrication of the pump and injectors. lubrication additive is supposed to be added prior to distribution but who knows ?