I would suggest to you, to check your fuel pressure. If you fuel pressure is low (below 20psi) then you can have a few problems. Dirty fuel filter, dirty pre-filer, fuel heater could of burnt and is letting air into your supply line (just delete that little sucker), or you lift pump needs replacing.

With low fuel pressure, your mileage will take a hit. Also your tires and lift will decrease MPG as well.

 

Get rid of those over-sized tires. The larger/wider tires increase rolling resistance and rolling mass. You have to burn more fuel at the same speed with over-sized tires to overcome friction and rolling mass then you do with stock size tires.

This will gain you a considerable amount of mpg's, up to 3 mpg in some cases.

 

"STAR WHEEL CRANKED" is your problem that is a 16 year old kid mod that wants to roll coal on every one it doesnt add power it just allows more fuel at low boost. My dad has a 98 12v and gets 18mpg with 35" toyo open countrys

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also if your fuel plate is pushed all the way forward or the most powerful setting it will hurt your mpg and driving habits play a big part in diesel trucks mpg. put something under your go pedal to keep you from using full throttle 3/4 should be plenty and Ill bet you will get much better mpg

 

I agree with 1993firstgennewbie ..... too much fuel line right off the line will kill it quick .... put your fuel plate about half way and spin your star wheel about 2 turns twards the fender .... you will pick up more mpg's ..... also run a quart of ATF in your next fuel up and drive freeway for a bit ... the detergents will clean out your injectors ... Proven to help ... ask 97cummins

 

yup

 

I get the same MPG as you do I've driven it hard I've driven it like a grandpa and in between there on different tanks of gas hasn't made a damn bit of difference I put Lucas gas additives in mine got 12mpg for that tank I wouldn't recommended getting a gas additive more then once sliding the fuel plate decreases your MPG but definatly gives you more power the comment on this page is BS because I have tested it I like the power so I left it you might get smaller tires if you care that much. A s&b cold air intake might bump it up a little bit good luck man let me know if you find and good MPG fixes I'd definatly like to fix mine but I'm not putting on smaller tires and moving my fuel plate

 

atf in the fuel?? tell me more!

 

ok... well ATF has bunches of detergents that when burned burn hot and helps with combustion by slightly raising compression and lubricating the cylinder walls .... its not a dramatic amount.... but by burning these detergents the varnish, gum buildup , and carbon will begin to loosen up and pass through your exhaust .... then your left with a nice spray pattern ... I can get u pictures of an engine that ran ATF and on that ran nothing for a supplement.... Huge difference ... try 1 Qt. per tank for two tanks ... you will notice more power and mpg I can promise you that ... ask 97cummins he now swears by atf in the tank now too .... one guy I work on his 24v and he has had a super chip since day 1 ... straight piped his exh. and put atf in tank ... 2.4mpg's and that's pulling a 10K trailer everywhere ... says he has to back out on hills because he's speeding ...LOL

 

Used atf or new? I know a lot of guys with older fords can actually run on used atf fluid as fuel

 

This "...detergent in the ATF" myth thing has got to stop.