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Old Feb 12, 2006 | 07:19 PM
  #1  
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Poor Mileage

I have a 00 SD SuperCrew, 4X4, auto trans, w/ 200,000 miles. The truck once got 19 hwy and 16 town (@143,000 miles).. It suddenly dropped to 13-15 hwy and runs about the same towing. I've replaced two injectors, and the inj wiring under the valve covers. Nothing has increased fuel economy.. I have no diveability problems and nothing coding in computer. All sensors are in proper range. It's due for a trans fluid change, other than that, all fluids are changed at their proper intervals. Fuel additives had no effect. The truck runs great with no problems and plenty of power.. where did my fuel economy go??? any suggestions???
 
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Old Feb 12, 2006 | 07:22 PM
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maybe you are starting the get the effects of winter-blend diesel. the winter-blend has the anti-gel additives in it, and the space that the Anti-gels' take up is space where BTU's are lost. less BTU's per gallon= less heat= less efficiency. whats your climate?
 
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Old Feb 12, 2006 | 07:24 PM
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check your filter lately? Where do you live? It might be due to poor fuel.

*EDIT* Strokin beat me to it.
 
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Old Feb 12, 2006 | 07:25 PM
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Well, I thought that too.. But, I've had this problem since last summer. I continued to test different driving conditions, additives, etc... nothing changed.. What's your opinion on AMSOIL for the PowerStrokes?
 
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Old Feb 12, 2006 | 07:26 PM
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I live in SW Missouri.... K & N stock replacement Filter....
 
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Old Feb 12, 2006 | 07:27 PM
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Originally Posted by SNIPER168308
Well, I thought that too.. But, I've had this problem since last summer. I continued to test different driving conditions, additives, etc... nothing changed.. What's your opinion on AMSOIL for the PowerStrokes?
keep it AWAY from the engine. but it is safe to use anywhere else. the amsoil is not rated for the HEUI injectors, it doesn't have the shear strength that other oils typically have (BTW i learned that this past week in Diesel tech )
 
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Old Feb 13, 2006 | 11:51 AM
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Don't know,,,,I have a 01 350 4x4 crew with 285 tires and thats all I have ever got in mileage 15-16 highway 13-15 town,,, kinda figured thats what they would do
 
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Old Feb 13, 2006 | 03:22 PM
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I wonder about fuel pressure loss, clogged inlet to the fuel pump, worn out fuel pump, injector spray pattern??? All these would explain why the loss of MPG's. When I replaced my fuel filter, I gained 1 MPG. So that leads me in the direction of getting good pressure, good fuel timing (CPS?) and good volume. Anyone else get an improvement after changing something for the fuel system?
 
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Old Feb 13, 2006 | 03:28 PM
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too late for me, already running Amsoil with good results.........100K miles. I have heard far more good about amsoil than bad, hope it worls ok for me.
 
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Old Feb 13, 2006 | 07:30 PM
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My first thought was perhaps winter diesel.
 
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Old Feb 13, 2006 | 08:31 PM
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I'm running Amsoil in my 02 F350. My friend has been running it for 2 years now with no problems. He gets the Blackstone oil analysis check with every filter change. Yes I did say filter change. He has not change his oil in over 2 years. The check comes back with no problems. I'm putting the Amsoil dual filter by-pass kit this weekend.
 
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Old Feb 13, 2006 | 08:51 PM
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Originally Posted by Dually02
I'm running Amsoil in my 02 F350. My friend has been running it for 2 years now with no problems. He gets the Blackstone oil analysis check with every filter change. Yes I did say filter change. He has not change his oil in over 2 years. The check comes back with no problems. I'm putting the Amsoil dual filter by-pass kit this weekend.
I also ran Amsoil's 15w-40 Marine Heavy duty diesel blend for 6k miles with an awesome UOA report.
After some extensive research i'm switching to Scaeffer's 7000 Supreme blend because they use two key ingredients in their oil:"Oil soluble, liquid moly, Molybdenum Trialkyldithiocarbamate, MoTDC, is excellent in engine oil and hydraulic oil, as well as gear oil and grease," and Schaeffers motor oil is also high in anti-foaming agent which is good for HEUI injector engines.
Nut
 
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Old Feb 13, 2006 | 10:02 PM
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how long have been running your k&N air filter?did you just clean it latley? (Just a thing I read in another forum)The oil from your K&N filter maybe coating one of your sensors in your intake telling it to use more fuel! I had the same problem but haven't done any thing about it.I don't know if this is true but it made me think about it! I read it in 6.0 ford diesel forums.
 
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Old Feb 16, 2006 | 08:06 PM
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Good Point.. If I Remember Correctly, The Mpg Steadily Declinded Not Long After I Installed The Filter.. What Sensors Would You Remove And Clean? Locations?
 
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Old Feb 16, 2006 | 08:30 PM
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Originally Posted by strokin_it7.3
keep it AWAY from the engine. but it is safe to use anywhere else. the amsoil is not rated for the HEUI injectors, it doesn't have the shear strength that other oils typically have (BTW i learned that this past week in Diesel tech )
Sorry to go back so far in thread, but I just read this portin. I currently run AMS oil in my engine because the owner before me ran it. I get about 17 around town(6 spd.), and I have had any problems. I don't want to run a bad oil, but is ok to switch synthetics like that. From what I've heard its no good. I want to continue running a synthetic oil any suggestions?
 
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