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Unbelievable MPG increase


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I just replaced all injector & fuel rail o-rings. I cleaned up electrical conections to injectors & seafoamed fuel tank. With fuel prices rising this is a must for older MJ's. Now my MANCHE is the envy for MPG's in our town. :smart: comanche.gif :Canadaflag:

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Back when it was bone stock, my 4.0/AW4 got 24mpg on the highway as long as I kept the speed down to 60. And that was with the original Siemens injectors. I replaced them for some better Bosch ones, but I can't compare as I'm not anywhere near stock anymore.

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Unless you had some massive driveability issues, a manual injector cleaning wouldn't give you a 100% increase in fuel mileage. Are you sure your math is correct? I mechanically cleaned my injectors too but it gives maybe 1mpg and mostly it provides balanced running.

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When I drove my '92MJ back from Ohio, cruising around 70-75MPH, I was pulling 24MPG with a bed full of parts and a dog in the passenger seat. Mostly downhill driving, though. Doesn't do more than 15-16 around town.

 

4.0L, AX-15, and 2WD. Great combo for highway mileage :D

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17 mpg in my 91 2wd LWB auto with a leaky sending unit...

 

20 consistantly with my 88 SWB 2wd with 216k...

 

13 MPG in my 08 STOCK cummins :ack: friggen emmissions :fs1:

 

Needless to say my 30k truck does not leave the yard much....

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Well fooey. My fuel gauge stopped working and with all these numbers being thrown around I have no idea what mine gets. 4.0 auto but its bored .010 with pistons and an HO camshaft :dunno: I thought 15 would be safe, maybe I should downgrade to 12.

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Don't need a gauge to figure mileage. Just the gallons from your fuel receipt and the miles from your odometer. Divide the amount of fuel you just put in by the number of miles since the last fill up.

 

You do have to fill the tank to the same level (usually full) each time, though.

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I'd have to fill the tank full because I don't know what's in there to begin with :dunno: And with gas so expensive and me not driving it often, I don't really want to do that. And, if I ever had the thing off road we all know that a few gallons could easily be spent in a few miles.

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