Just a word about additives. I communicated with an engineer at Stanadyne about additives, and have done some research about it. He said that they have been making their additive and improving it since the late 70's, early 80's. They make fuel injection equipment, and know how to protect it since fuels have changed and sulfur content has been mandated lower for emissions. He also stated that we should be skeptical of an additive that is both for gas and diesel as the two are different. I have used the Performance Formula since the early 80's and have operated several near 200,000 mile vehicles without a fuel pump failure! I know it works! This additive is one of the few endorsed and recommended by Ford, GM, Navistar, Deere, Caterpillar, VW, Volvo Penta, and AM General. Short term improvements don't mean much with fuel additives. Longevity and protection are the keys