So I noticed that everytime I fill up my tank with the usual 93 octane, my truck sudden gains pep. Like it opens up. Then about a day later it loses some of its get up and go that it gained with the gas. Why does this happen? My fuel filter is no more than 2 months old, gas tank/sender unit about 2 years old. It doesn't matter what station I go to, but usually I go to the local Hess station.