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Discussion Starter · #1 · (Edited)
So being new to diesel I’m sure the winter blend effects mpg and performance just like everything else but I’m half disappointed how poor the performance is on my l5p the last couple months. My mpg dropped by 3 and it’s just lacking the punch.

Pulled the tmap and cleaned it just because but there was next to nothing on it, and it tops out at 40lbs of boost at wot so I doubt I have a leak. (edit apparently with the scan tool you have to subtract the boost at idle 14 so it’s really 26Lbs of boost) only thing I can think of is the winter blend is just that bad? Is it?
 

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2015 High Country Duramax
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Depending on the fuel, it can be treated with additive to prevent gelling, or it can be a mix of #1 diesel and #2 diesel. The #1 diesel is essentially kerosene, and as such doesn't cloud up like #2 diesel does.

However, the #1 diesel has a lower BTU value, which means less power. It isn't a substantial difference though, only a couple percent less.

Not all fuel suppliers mix fuel anymore though. Additives are cheaper and easier to add instead of mixing the fuel. It also varies by area of the country. Here in PA around me, it is just treated #2 diesel. I can tell when they switch because it has a slightly different smell to to as well.

When was the last time your fuel filter was changed? You can try to run an additive with a cetane boost to see if that does anything for you. I'd run an additive anyway to help with the lubricity of the fuel since modern diesel is lacking in that department thanks to the ULSD requirement. I run optilube xpd year round. It has added lubrication, some anti-gel, and bumps your cetane a touch (that's not it's main function though)

Power service in the grey bottle is also good, as is hot shots EDT, and various others.
 

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Discussion Starter · #3 ·
Have a can of the Schaeffers winter treatment but have yet to use it, it’s not really all that cold here but we are headed under north shortly.

Fuel filter was changed in august right before I bought the truck, says it’s at 74% for what ever that’s worth. Had a new 1500 at4 drop me like a bad habit getting on the freeway the other day and that just kinda sealed for me that the truck is lacking a bit. My truck will still brake em loose from a 40 mph roll. Starting to think I just need more


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Your L5p should pretty well spank any 1500 unless its a 6.2, especially a 6.2 10 speed truck. Those will hold their own and then some lol.

How long has the lack of power been going on for that you've noticed?
 

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Discussion Starter · #5 ·
The last month or so. Might jump fuel brands the next tank. Arco is far from the best option out there but they turn fuel quick as it’s one of the cheapest stations in my area.


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