Not idling right during start up/high idle mode

[RamGuy110]

I have a 2021 Ram 2500 Cummins. This is my 4th Cummins, a 2018, 2019, 2020, 2021 and I've never experienced this before. Since its crazy cold here just about every morning, I just noticed on Wednesday that when I start it, it will go into high idle mode to warm up. That's normal. It usually sits around 900 rpm until you press the brake pedal or put the truck into drive. Since Wednesday I've noticed that while its in high idle mode, the truck sputters, shakes and the rpm's fluctuate, almost like its getting choked off. I thought for sure it was going to shut off a couple of times. Driving around, its normal. Any thoughts? I've never had this happen before and have been in the same temps, etc hundreds of times over the years.

 

[KKBB]

Partial fuel gelling maybe?!?!

 

[KKBB]

Mine would stumble somewhat at times too, but never seemed like it was going to die. Grid heater kicking on and off will drop rpms for a bit too.

 

[RamGuy110]

Yes, I know the grid heater fluctuating, but never seen it act like this.

 

[RamGuy110]

Partial fuel gelling maybe?!?!

The fuel from Holiday is supposedly treated to -30 degrees. That tank however I got at Sam's club and added some Howe's diesel treatment to it, so it shouldn't gel.

 

[Dean2]

Run through this tank of fuel and go back to your regular supplier. It gets pretty cold up here. Fuel quality makes a tremendous difference in low temperatures.

 

[KKBB]

Run through this tank of fuel and go back to your regular supplier. It gets pretty cold up here. Fuel quality makes a tremendous difference in low temperatures.

View attachment 486369

Run through this tank of fuel and go back to your regular supplier. It gets pretty cold up here. Fuel quality makes a tremendous difference in low temperatures.

View attachment 486369

I would definitely move somewhere warmer if I were you!!!! Haha

 

[RamGuy110]

Well today, my DEF see dealer for service light popped on and then the check engine light came on and DEF 130 miles until speed reduced to 5 mph. UGH

 

[Dean2]

If it is cold enough DEF has been known to freeze up if it is cold enough.

 

[RamGuy110]

50 degrees today, but yeah I know.
I took it in today (dropped it off), got a rental 3/4 ton from Enterprise. The advisor at the dealer told me they've been seeing a lot of this this winter, way more than any other winter season. He said they drain the system and take it apart, lube and re-assemble and that usually solves it. If the pump is no good, I'm sol he basically said though. Worth noting that the Enterprise guy told me almost all of their Ram diesels have had def issues and have had to be serviced this winter. I took a 6.4 Hemi for the rental.