I rounded up a few things that may help get better MPG:

EGR failure (waitng on dealer for parts), + .5MPG
2.5" muffler, +.5MPG
44PSI tires, +1.5MPG
cetane additive, - 1MPG
full time 4x4, - .5MPG
Cheap B20 Biodiesel, - 1.5MPG

based on the average of 20 tanks with a '06 CRD. hope this helps!

What fuel Cetane booster were you using? -1 mpg??? I use Power server occasional and may not see much of an increase but my experiance hasn't been a step backwards. I did change over to BF Goodrich TA KO's load range D and run them about 40 PSI seemed to be good for 1 or 2 mpg.

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Sold 05 CRD Patriot Blue, hole in the roof, Trailer tow, factory skids, LSD, Saris load bars, Michelin LTX M/S
Current Bright white 2010 Dakota Quad Cab 4x4 V8

8-10 oz of powerservice antigel & cetane boost mixed with about 15 gallons diesel. I think that's between the min and max treatment.

I do have the regular PS cetane boost to try when I run out of the other stuff.

The anti-gel Powerserve only boost the cetane by 3 but the regular Powerserve boosts the cetene as much as six. Personally I think that all of fuel economy will get better when they quit selling the winter blend fuel. Now that I have 16k miles and the engine is starting to break the fuel economy should be in the upper twenty's.

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Sold 05 CRD Patriot Blue, hole in the roof, Trailer tow, factory skids, LSD, Saris load bars, Michelin LTX M/S
Current Bright white 2010 Dakota Quad Cab 4x4 V8

They started to change the blend in Minnesota for the warmer weather. My mileage has gone up about 2 mpg with the last fill up. I am getting about 21 mpg in town.

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Gasoline is for washing parts - Alcohol is for drinking - Nitromethane is for racing - Diesel is for hauling.

2005 CRD Limited 4x4 - Deep Beryl Green - Selec-Trac
Trac-Lok - Skid Plates - BFG Radial Long Trail TA's- Rotella T 5W40 Synthetic.

2007 GC CRD Limited. Silver.

I'm up to 17.5 in town now with the better blend up here in Superior Wisconsin. Running my Predator seems to be good for 1 mpg.