I took my 08 Dodge Ram 1500 4.7L into the dealer because of the check engine light. It recently dropped into the lower 30s here in Texas. I was told that the error they got was a "Cold start rough idle" error. They told me that they had to call Chrysler and they were told that with some of the newer vehicles on rare occasions in the colder weather the sensors are trying to adjust to lower fuel quality and tripping the error. I currently use the 87 octane and was told that until the break in time, I should use a mid or premium gauge fuel to keep this from happening again. I only have 1200 miles on the truck now and was told that I should use a higher grade fuel until about 3000-4000 miles.

Has anyone else ever heard of this?

 

I have not heard that before. I used reg 87 to break in my truck. Maybe try a high quality name brand gasoline and see if it helps.

 

Sounds like a crock of **** to me. Some dumb excuse it seems like. See if the higher grade gas works.