Help Me! Horrible Gas Mileage!

[Jerry Gerner 2]

Ryan, it only cost the amount of the cleaners ($12most) to clean the MAF, TB, IAC, and it'll help out alot.:banana:

 

[Richard L]

Ryan,

Running the truck till the tank is empty and filling it back up does not mean you have an accurate MPG reading.



To know how much gas you used, you must know how much gas was in the truck when you started. That's why I said that you should first fill your tank until you see the gas at the filler neck restrictor. Now drive for at least 100 miles and then return to the same pump and again fill the tank until you can see gas at the restrictor plate. The gas pump reading will tell you exactly how much gas you used on your MPG test.



Obviously the more miles you drive the more accurate and realistic the MPG average will be, and the most accurate MPG averages are best taken over a minimum of 4-5 tanks full of gas. The method I just explained is good for a quick trip or over a few daily back and forth to work commutes. The longer fuel mileage test will average out a lot of the other factors like traffic, weather, etc which can have a much larger effect on a quick test of only 100 miles or so.



...Rich

 

[Rich Erickson]

Do you have a bed cover or tonneau? Drivin' one of these at speed with an open, empty bed is like dragging a little parachute... mpg will suffer.

 

[Richard L]

Rich,

That is now a false assumption. The Myth-Busters TV showed that modern trucks generate and air bubble in the cargo bed that allows air to flow smoothly over the bed and over the tailgate. A tonneau cover makes little difference.



Mileage tests done on this site years ago show that there is not significant mileage improvement for the ST with the tonneau cover vs and ST without the tonneau cover. Until I saw the proof on the Myth-Busters, I thought the reason was related to the shorter ST pickup bed, but it appiles to all pickups. Removing or lowering the tailgate actually reduce fuel mileage in the Myth Busters test. The windtunnel and submerging a model in a tank of flowing water with confetti confirmed the bubble theory and clearly showed how the turbulant air formed a bubble in the bed and the air passed smoothly over the bubble. So it is not even close to acting like a parachute as most people think.



...Rich (The other Rich)

 

[Rodger Tellefson]

Ryan,



I'd replace the air filter with a decent stock replacement, and replace the fuel filter too because they "may" never have been replaced. Should run you $20-$25. Not that much money and will help tremendously. I too agree with the replacement of the PCV and cleaning the MAFS, throttle body, Idle Air Control motor (see projects under Maintenance). My judgement is that getting better mpg will be a combination of things, not just doing one thing. Can you get a maintenance record for the vehicle? I feel that will be of help as a starting point.

 

[Rich Erickson]

Rich,

That is now a false assumption. The Myth-Busters TV showed that modern trucks generate and air bubble in the cargo bed that allows air to flow smoothly over the bed and over the tailgate. A tonneau cover makes little difference.



Mileage tests done on this site years ago show that there is not significant mileage improvement for the ST with the tonneau cover vs and ST without the tonneau cover. Until I saw the proof on the Myth-Busters, I thought the reason was related to the shorter ST pickup bed, but it appiles to all pickups. Removing or lowering the tailgate actually reduce fuel mileage in the Myth Busters test. The windtunnel and submerging a model in a tank of flowing water with confetti confirmed the bubble theory and clearly showed how the turbulant air formed a bubble in the bed and the air passed smoothly over the bubble. So it is not even close to acting like a parachute as most people think.



...Rich (The other Rich)

Well, I stand corrected! And surprised. Good info! You may have even saved me some $$, as this was one of my internal arguments for getting a tonneau for my ST...



...Rich (the new Rich)

 

[mookie]

Isn't it true that they used a Dodge Dakota regular cab/bed for this test? This is a different shaped vehicle than ours (crew cab/short bed) so the results may not translate.