Basicly I saw alot of comercials on tv and TV shows talking about this topic and come to 2 conclusions: #1 they're either full of shit or they're uneducated trying to gain some knowledge and have been mislead. here's what you can do to help optimize your MPG's no matter what you drive. I will also dispell any myths concerning any products out there to the best of my abilities.
#1: Check your tires and make sure that they're properly infalted. Bigger tires also tend to use more fuel because you're increasing the rolling resistance more than your stock tiresize.
Myth: Advertised fuelsaver tires save you money at the pump.
Facts: this is a YES and NO answer. YES if your tires are worn and have basicly little or no traction. NO if you're replacing them based on the claims.Here's why: Goodyear advertises their fuel max tires during Nascar races. But people FAIL TO LISTEN TO THE CLAIM. They specificly state that the tire does save you fuel "OVER THE LIFE OF THE TIRE".
#2: Drive slower and avoid high winds and interstates as much as possible. By taking local highways instead of interstates your not putting a much stress on the engine and your cruisng at lower rpms so your fuel consumption is therefore less than normal.
Myth:dropping the tailgate helps with mpgs.
Fact: I use to believe this until I saw the Mythbusters episode concerning this. You LOSE MPG'S BY DOING THIS. The only time that lowering the tailgate really helps is if you have to drive in EXTREMELY HIGH WIND GUSTS OF 40 MPH'S OR MORE. The only thing you can do is invest in a fiberglass toneau cover to help reduce drag.
The Ultimate fuel saver is : WEIGHT REDUCTION BY OVER 1/2 AND BETTER AREODYNAMICS.
Cold air kits: some work and most don't. yes colder and denser air helps but what good will it do you if the engine draws the air from the engine bay only? you need to "reroute it" to draw in colder air. The reason I say that most don't is because of the reason stated earlier and the materials used in these kits. the composite tube is heated pretty quickly. So you go to aluminum. Well guess what? you just defeated the purpose. Aluminum will heat up just as fast if not faster than composite will. The reason: Composite is an INSULATOR TYPE MATERIAL. ALUMINUM IS A CONDUCTOR TYPE MATERIAL. That means it will conduct heat faster. here's the only thing about CAI's that are useful. They flow better and that's it. here's another thing that you can do if you have installed a CAI kit: PURCHASE A HEATSHEILD FOR YOUR INTAKE TUBE. that will be a big help because your CAI system is pretty close to components that produce extreme amounts of heat. and basicly with no where for the heat to go, naturally that CAI tube will get hot. The heatsheild will block the heat and thus making your intake charge kooler. Now there are some manufacturers out there that do realize and test their products for this paticular purpose so please look at the types of materials before you purchase a CAI kit.
Also stay away from products that make outrageous claims for fuel savings. "If it's too good to be true, then it isn't". A prime example: The Tornado(Or what ever it's called now). For awhile people fell for this scam many times over. That list includes techs, car gurus, fleet owners etc. It's about 2 zillion miles long. I myself fell victim to this. Then I watched dateline concerning the fuel crisis in 2007 and 2008. They investigated all products and found 3 out of hundreds that actually work: Lucas Upper Cylinder lube, Seafoam, Stabil Fuel Stabilizer. That's all that lived up to the advertising.
#3:Change or clean your airfilter at reguarly scheduled interavbles. By letting your engine breathe better you'll optimize your vehicles mpg's and performance.
K&N Air Filters:
they're good and have an excellent warranty but tend to be expensive. I would recomend using Speed by spectre performance. The warranty isn't quite as extensive as K&N's but they're cheaper. $25 bucks for a nearly Identical air filter that costs twice as much.
#3: Exhaust and retuning: This will generate debate but oh well. by changing your exhaust and retuning it for reduced back pressures you'll also see an increase in mpgs because yet again you're letting your engine breathe better.
And for those who doubt my skills or knowledge here's a photo for you: