MORE NEW FUEL-ECONOMY ADVICE* MPG GEEK: 10 Quick Fuel Efficiency Tips to Save GasFor nearly 20 years, I’ve been giving all sorts of advice in my Saturday Mechanic column on how to improve fuel economy. Much of it has been fairly routine, like checking your tire pressure or tuning up your engine. And some has been plain-old common sense, like not flooring the gas pedal. Most folks forget about that last one. And while a new crop of so-called ecomodders like our guest MPG geek Benjamin Jones do a nice job of developing a new trick here and there, the real fear when gas prices get this high may not be so much what you pay at the gas station as the snake oil everyone’s trying to sell outside of it.As legitimate analysts and agencies continue to threaten that the gallon can well exceed four bucks, other seemingly reputable sources are once again firing their silver bullets from the sidelines of the automotive industry. And once again, a lot of what I’m hearing is based on urban legends and a general lack of understanding about how cars actually work. What’s worse, these people have agendas. And those agendas include removing money from your pocket by selling you stuff that’s supposed to improve your fuel economy. Let’s poke some holes in the new hype.Myth No. 1: Cold-Weather Fill-er-UpsMyth No. 2: The Clean Air-Filter SwapMyth No. 3: Going PremiumMyth No. 4: Tire InflationMyth No. 5: Cutting the A/CMyth No. 6: The Gadget ConMyth No. 7: Short-Stop IdlingRELATED STORIES* MPG GEEK: 10 Quick Fuel Efficiency Tips to Save Gas* SATURDAY MECHANIC: 13 Tricks to Max Out Road-Trip MPGs* LAB TEST: Mike Debunks MPG Gadget Hype in the Garage* ASK MIKE: Send Your Questions for Mike’s Online Column!