Disappearing fuel mileage

Dirtymaxx03

Active member
Aug 4, 2009
3,109
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I need some help on ideas as to what is causing my fuel mileage to go to crap. Used to get 17-18-19 mpg's no problem with mixed driving, these days I gotta fight to get 15-16. Truck is not making oil, no rough idle, no white smoke. The only thing wrong with my truck right now is possibly a drive pressure leak due to a hole in the passenger side up pipe. I don't think it's very big because the truck makes boost just fine. Another thing that could have caused it is the fact that I am running without a lift pump. So what say y'all? Could a small exhaust leak kill fuel mileage that bad?
 

Balindir

Rod shortning in progress
Jul 30, 2012
364
0
16
South Central, Pa
I wouldn't think it would that big of a difference if its like a pin hole... but then again, it certainly isn't going to help your cause...
 

Dirtymaxx03

Active member
Aug 4, 2009
3,109
1
38
Yeah its gonna get repaired along with the hole in my down pipe, i just have to get the motivation to battle the up pipe bolts :mad:
 

Dirtymaxx03

Active member
Aug 4, 2009
3,109
1
38
I am half tempted to sell the truck instead of messing with those stupid manifold and up pipe bolts. If that tells you how much i hate them
 

bluecollar

Member
Feb 28, 2012
351
0
16
ia
Are you goin off hand calculations or computer.. i know when my cp3 was returning to much fuel i dropped to 3-4 mpg on the dic.. not saying thats the issue
 

Dirtymaxx03

Active member
Aug 4, 2009
3,109
1
38
No fancy computer read out mileage on my truck. All hand calculated. Idk where my fuel has been goin the past couple months but this whole 350-360 miles to a tank is bullshit
 

blk smoke lb7

<-----Lots of green $
Nov 8, 2010
5,694
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57
belvidere,ill
Yeah I have no idea where mine went either ever since the second turbo was installed :roflmao:

Time to sac up and git er done.they arent that bad.
 
Last edited:

weazel

Member
Oct 5, 2011
261
0
16
44
Mason, TX
No fancy computer read out mileage on my truck. All hand calculated. Idk where my fuel has been goin the past couple months but this whole 350-360 miles to a tank is bullshit
same here... on both of my trucks... starting to feel like the old days running a 454, couldnt pass up a fuel station without having to stop to fill up! :roflmao: