I bought my CRD on 6-01-06 and from 500 - 4,849 miles I kept track of every gallon that went into the tank.

4,349 miles driven, 177.21 gallons used = 24.54 mpg. 100% LSD Pre F37

I decided to track the the fuel usage again this year.
Started keeping track @ 25,778 miles until 29,736 miles

3,958 miles driven, 150.14 gallons used = 26.36 mpg. 95% ULSD 5% LSD( Some stations around here still sell this) Post F37.

Both readings were through the months of June and early July so the weather was about the same. The only difference is the miles on the vehicle, the F37 and ULSD vs LSD. I did change the driveline fluids, front/rear axels and diff, with Amsoil but can not imagine this would add almost 2mpg. I can only hope that this will improve more with more miles, just turned 30,000 miles this AM.

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2006 CRD Sport

Break in will affect MPG...I think ULSD with a slightly higher cetane rating than LSD also helps.

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Founder of L.O.S.T.
2006 CRD Sport
Mods: GDE Hot Tune w/ 364#@2000rpm/Air Box /3" Str8 Exhaust/ASFIR Alum Skids/245-75R-16 Cooper STT PRO/OME LIFT w/Clevis & 4 Spring Isos/AirTabs/Rigid 10" S2 LED/4xGuard Ctr Matrix Bumper
Drag Strip:Reac=.1078_60ft=2.224_1/8=10.39@64.8mph_1/4+16.46@80.8mph

What he said, plus the Amsoil synthetics didn't hurt either. A combination of all I'd say.

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Mitchell Oates
'87 MB 300D Diamond Blue Metallic
'87 MB 300D - R.I.P. 12/08
'05 Sport CRD Stone White
Provent CCV Filter/AT2525 Muffler
Stanadyne 30 u/Cat 2 u Fuel Filters
Fumoto Drain/Fleetguard LF3487 Oil filter
V6 Airbox/Amsoil EAA Air Filter
Suncoast TC/Shift Kit/Aux Cooler
Kennedy Lift Pump/Return Fuel Cooler

Since returning from our vacation to FL I have been averaging 27-29 mpg driving mostly 60-65 mph. Using USLD splash filled with biodiesel at about 10-20%.

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08 Elantra SE daily driver
2001 F-250 powerstroke

I am just turning 30k as well. I have the 150hp programmer in mine and when on FE mode I fetch almost 31mpg if 70mph and about 30.2 if I set cruise at 75mph. When new she would only get aout 26+. Yes I also check it with a calculator when I fill up. I want to put a larger tire(235/75 or 245/70?) on it soon but am worried it will eat up my MPG.

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2005 CRD Black Limited SP'd
2001 MB E320 Black
1987 MB 560SL Red MINT
1980 Corvette Purple 400hp
2001 HD soft tail Deuce Black
1985 Honda ATC 250SX Red