Grand Prix 500
Join Date: Aug 2010
Location: Texas Hill Country
Marvel Mystery Oil has been around for many years. Well before STP for those of us old enough to remember that. It's a petroleum distillate that inhibits the formation of water droplets in gas, diesel and oil. It's also a lubricant and detergent. If your fuel system is dirty you can restore fuel economy to that of a clean engine. A good synthetic oil (the real cause of STP's death) will provide the reduced friction factors that drain engine efficiency.
Stabil and STARTRON both break up water droplets in the fuel tank. The STARTRON difference is that is enzyme based as opposed to petroleum distillate based Stabil and MMO.
The biggest thing standing in the way of better fuel economy in the U.S. is the government. The mandating use of ethanol to "stretch" (dilute) the fuel supply reduces the mileage of gasoline by nearly as much as it adds to the amount of fuel available. The result is that we are not getting any farther down the road, and paying more for it. The key is to restore the missing energy (rated in BTUs) ethanol takes away from a gallon of pure gasoline. Methylcyclopentadienyl manganese tricarbonyl (MMT or MCMT) a replacement for TetraEthyl Lead (now only available in Aviation fuel in the U.S.) has been used as an octane booster for many years. In and out of favor with the EPA, the Canadians have used it for years (except for brief time in the late 90s) and Australians now have it. I don't know if MMT plays well with ethanol. I haven't heard of or seen any studies on the matter.
I've used MMO for years. With brand named (Shell, Chevron/Texaco and Exxon/Mobil) detergent fuels. At 48K on my wife's car I still had to drop in a can of 44K to stop the pressure sensor from turning on the "Check Engine" light indicating that the gas cap was loose when it wasn't. Her mileage was slipping before and improved after the 44K as well. I guess there is no Magic Bullet in any one product. You will need a specific product to resolve certain issues as they arise.