Rail Pressure Difference
 

Recently ventured south for the holiday and upon return we went from roughly 60ºf to 30ºf in a short time. This truck is a 2003 and I've had it since it was new and it has been like this since I can remember.
My question is, running at 70mph the rail pressure bounced between 12-13g's @ 50ºf +. Then running the same speed @ 27ºf or less the rail pressure bounced between 8-9g's. I've wondered this for many years.
The smarty pants at Dodge have this happen for emmisions or do I have a 18 year issue (LOL)
Thanks

Neither one, IMHO. Diesel is less viscous when colder and may be beginning to gel. If you are going through a cold area after fueling in an area that uses 'summer' fuel year round, you may have gelling issues. Best to put some anti-gel product (Power Serve, Howes, etc) in your tank before you fill up (so it mixes well). Gelling starts at about 32* and gets progressively worse as the temp drops.

BTW, loved my '03 2500.
Back to morning brew . . . [coffee]

FMB
Good answer and I understand the gelling. Happens all the time in my skid steer getting caught with a tank of warm weather fuel (a little 911 works everytime).
But the pressure difference is the same with winter fuel. 70mph , summer 12-13, winter 8-9.

Thanks for the reply. I'm no expert so it's easy for me to get stumped. I also haven't spent much time in the frozen areas of the country and when I did I don't remember noticing any pressure differences in my '03. Hopefully, someone from the frozen north will chime in.
Back to morning brew . . . [coffee]

As I now have more miles behind me than in front, I think about putting the snowblower in the back of the truck heading south and stopping at the first
place that someone asks, "what's that thing for in the back of the truck....."
Have a blessed 2022 FMB.

Have a blessed 2022 yourself and stay safe tonight. :)