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Discussion Starter · #1 ·
Last tank was about 11mpg, unacceptable.
Drove with an egg under the pedal foot.
The truck had been sitting prior to my purchase, it now has 115k miles.
Some things have come unstuck, the oil pressure gauge works at idle now.
Where would you look to eliminate obvious troublespots?
 

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If it sat for a while before you bought it, I would do ALL of the vehicle maintenance. Knowing that everything is in proper working condition will help further diagnose issues. Poor mileage can be caused by many things.
 

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If the truck sat for a long time the fuel may have lost its oomph. Not only would it lack power it would also burn quicker. Your next tank will also see lower than normal mpg because you most likely still have around 10 gallons of old fuel left. The tank after that should see better mpg.

Is your filter minder sucked down? You may need a new air filter.

Sit the truck on a slight hill. Put it in neutral. Does it want to go downhill or does it stick in place? Sticking brakes can affect fuel mileage.
 

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Discussion Starter · #4 ·
Thoughtful responses, thanks.
Bought it in Tenessee, drove it to Maine, probably used up the bad fuel. Though it took that long for the oil pressure gauge to operate properly.
No observed fuel leaks.
Yes, the brakes are new, might stick a bit. Will check them out for drag.
Going to change the filters (gas and oil).
The fuel filter should not affect fuel mileage should it?
 

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I am still a cummins newbie but have had similar experience. I bought my 96 and it had sat for seven years. Drove it a couple hundred miles home and was only getting 12 mpg. Ran a couple tanks through it with no change. Did the bhaf, fuel filter, muffler delete and oil change and it went to 15. Started going through the beginners thread and did the afc mods, boost elbow and cleaned the prefilter and now I am at 17. I am not going to pretend I know which part of this helped mpg just letting you know what all I did and something worked.

Also I have 4.10 gears and if I run over 70 Mph I am right back down to 15ish.
 
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The extreme cold may be playing a factor as well.

My truck is drinking fuel.
 
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Discussion Starter · #9 ·
Many thanks guys. Great contributions.
Still not good on the acronyms: bhaf, afc and boost elbow.
It is some cold here so no doubt the winter fuel mix is hampering mileage also.
The seller made it look like he did maintenance and he did, just, well, some times you have to have owners TLC (Tender Loving Care), skin in the game, to go the extra little bit so that everything works just right.
Yes, more work to do, gonna get it right.
 
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