Engine/Transmission (1994 - 1998) Horrible MPG's

[Buck88]

Well, put 12 gallons in my new truck today, and it gave me almost 5/8 a tank. 40 miles later I'm at about 3/8 a tank. Gears are 4:11 and I'm not a lead foot driver. Could the timing have slipped on a stock truck? I know that the air filter is dirty. Haven't checked fuel lines yet. Help Please!!! - Thanks, Buck

 

[JSienkowski]

What are you running for tires, have you changed the fuel filter yet??

 

[Diesel Dually]

I don't think I would be too concerned yet. The fuel guages on these trucks give you a relative reading at best. My '96 will read full for about 150 miles, at 200 its at 3/4, 300 at 1/2, 375 at 1/4, then it will hang around 1/8 for about 100 miles or so and by about 550 to 600 it reads E. I have changed the sending unit and it worked better for about 15K then back to "normal". These trucks must have air so change the dirty air filter asap and if you don't know when the fuel filter was last replaced I'd replace that too. Then, fill'er up and hand calculate mpg at next fill up.

 

[BigPapa]

Welcome to the TDR!



The fuel sending units are notorius for failing. Mine hasn't worked for the past 2 years. I actually have my gauge covered up.



I would suggest filling completely up, driving about 250 miles, and fill up again. Reset your trip meter when you fill up, and check your mileage this way.



Also, check for fuel leaks. I've already had to replace my rubber fuel lines and the water drain valve on the bottom of my fuel filter. Both times fuel was just pouring out while the truck was running.



You might want to carry a can of fuel with you until you get an accurate check. Are you familiar with the fuel pump and how to prime it if you run out of fuel? It's very simple.



Scott

 

[bmoeller]

I go by the odometer, more than fuel gauge. I can run about 100 miles on E. My mileage is pretty consistant, as is the operation of the fuel gauge.



Hand calculate the mileage. Only true way to tell.



On my Ford, when the gauge reads E, for either tank, either tank is still half full.

 

[Buck88]

Thanks a lot for your guys' input, I appreciate it. Definitely going to change air/fuel filters, and I will hand calculate it. Thanks, Buck