Even worse fuel mileage ???

[05boosted250]

Was getting 9.2 on my truck with the Diablo set on street. Bumped it up to race and went down to 8.1. After awhile on race I went back to street, but the mpg never went back up. No real big deal so I wasnt worried. Then I got the power elbow and unplugged my EGR. Bout a week later my truck died cuz I was jamming out to the stereo for to long, so I had to jump my truck. Now my mpg reads 6.3 and with my heavy foot Im only getting about 150 miles before I need to refuel. What happened? Do I need to reset something? Thanks

[Goose]

are you going by your calculations or the computer

[05boosted250]

By the computer for all calculations.

[Goose]

push and hold the 2 buttons in to reset and those things our never right

[05boosted250]

Which 2, cuz there are 3? And if your referring to resetting the computer system so that it does all those checks or the other one where it does some other thing, Ive done those.

[Goose]

the two up on the roof just look and it sould have lines going to two of them and saying reset hold them

[Goose]

Click That

Overhead Console woes.

[720Deere]

I would say you need to do 2 things before you can say for sure that you have a problem. The first thing that I would do is run 10 miles down a highway with mile markers. You will be able to tell how accurate your odometer is by comparing it's reading to the measured 10 miles. I use 10 miles because it gives enough distance to get an accurate reading and it makes the calculations easy. Stay in one lane while you do this as weaving back and forth will mess up the actual distance traveled.

If you do this and your odometer only reads 6 miles then that is most of your problem. The second thing you need to do is accurately hand calculate your mileage. Take the time to fill the tank until fuel is seen in the neck (not just foam). Drive for a few days and refill the exact same way. Miles traveled divided by gallons used is the only accurate calculation that you can count on.

I don't know much about the Diablo, but my bet is that it has messed with the accuracy of your odometer. The only other thing that I can think of that would produce fuel economy that poor is excessive idling. The rule of thumb is 1 hour idle time equals 33 miles driven. I have found this to be fairly accurate. I get 13.5 to 14.5 mpg during the winter season and 15.5 to 17 mpg in the summer. The only real difference is the 20 minutes of warm-up time each day during the winter months. Two hours idle time on 33-34 gallons of fuel makes about 70 miles difference along with the 2 mpg drop.

If your truck has an hour meter, check the miles vs. hours. My truck sees a lot of city/commute miles and my average mph for the 16,000 miles on the truck is about 34 mph. This is a good check for idle time and fuel economy.