New fuel readings after lift (question about estimated MPG readout)

[King$nake]

I don't know why I just started noticing this, but before I lifted my 98 Eddie Bauer 2WD, the "Message Center" in my center console would read roughly "290 miles to empty" on a full tank of fuel, but after I lifted the truck and put 33" mudders on it, it eventually started reading "200 miles to empty" on a full tank. For whatever reason I just noticed this tonight after I filled the tank. Is it possible that the computer adapted? lol skynet is now online.

seriously though it's tripping me out. My gas mileage is horrible now, it sucks, its like 10-12MPG. I need to get the TM Headers, CAI, new plugs, wires and 4:30 gears, hopefully that will help.

Thanks in advance

 

[LONO100]

im not sure how your message center was picking up on the fact that you had bigger tires on, but you will generally get worse gas mileage the larger the tires you get. also, some of the other mods you plan on doing will worsen your gas mileage. the 4.30 gearing, headers, and possibly the CAI.

 

[4pullingGM]

If you havnt recalibrated the computer for the bigger tires your speedometer will read slower, which will equal less miles put on the odometer per tank of gas, so your message center thinks your not going as far on a tank of gas as you really are. Swapping the gears in my opinion should help the fuel mileage because the engine wont have to work as hard to move those big tires and the engine will be back in its power band. Plus you should notice a bit more power because the tire size/gear ratio relationship will be closer to stock than where you are now. I have also seen fuel mileage increases with cold air inakes. It is a lifted truck, so it wont ever get as good mileage as it did stock. But i think your plans are on the right track to recover some of it.