Okay guys I need someone to shoot some ideas at me.
Last summer I got 23MPG pretty easy (that's hand calculated and accurate)
The fuel mileage has been steadily dropping,on my last trip over to Portland I got 14mpg empty,and that's just sucky.
The head gasket is leaking a little antifreeze,but it's not bad,no leaking from cylinders as far as I can tell,my exhaust manifold is cracked a little,I've checked my AIT sensor and it's working correctly according to the chart I found.
The loaded mileage is still about the same,around 11-12mpg which I can live with.
Pulling is still pretty dang good,but man is this thing starting to cost me in fuel!

You guys think it could just be the dang exhaust manifold? it still makes 32psi....

 

Don't know if thats the cause or not but its deff. not helping... I'd start there for sure

 

That small crack you see in the manifold while your truck is sittin with no pressure on it will open way up once your putting some back pressure behind it and it's no small crack anymore. That's why they crack is because of all the flex. Your losin all your power through that crack and ya you can still get the psi but your engine and turbo are workin way to hard to get it there.

Definitely replace that manifold.

Personally I've never gotten anything better then 20mpg and that was when the truck was new. even with these 19.5 Rickson wheels with the big truck tires I still am not gettin any better then 18mpg when I drive old man style and I've been as low as 15mpg.

 

are you getting any antifreeze in your oil? if it's leaking into the motor etc I would imagine this could be causing some fuel mileage woes as the antifreeze doesn't burn like water meth

 

20mpg was more common,but if I didn't mind driving 55 then I'd get up there.
It's tough to go from being able the stretch a tank for 750 miles to having to fuel up at 400...it's making my wallet ache!
I'll order a new manifold today.(more wallet pain!)

 

I have to fuel my truck every 450 miles

 

Naw,it's just got the little leak at the front passenger side corner of the head,I'll replace the head gasket while I'm at the manifold,I just could not believe that that little crack was causing all that trouble,though I have been noticing that the smell has been getting more severe.

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And replace the tires every 20k too I'll bet!

 

Temperature warmed up,magically back to 18.5-19.5 MPG I guess maybe it's the fuel.

 

I got about 40k outa my last set and yes winter blend sucks *** for mileage

 

Hey, i was about to make a post of the same thing, Yet. i don't know if i have any exhaust leak or if the blend of fuel is any different' for now.

Should i thread jack ? or make a new one ?