What exactly, MC, is this "dealer tune" you speak of? You attribute your great mpg to it? I'm interested.
Goose, perhaps calling it a "dealer tune" could be a bit confusing to some readers. I was mostly trying to clarify that I have not yet upgraded to a custom tune designed to add horsepower. (Although I am still considering it to reduce some of the pedal lag, etc)
I wrote a bit about the issue on
https://hdrams.com/forum/index.php?threads/annoying-jerking-issue-update.1265/page-5. For those that can't access that forum link, from the factory my truck had a horrible surging problem like many others. I'll paste the basics below:
Problem: "surge" every 0.75 to 1.5 seconds if under a bit of load. Regardless of whether on cruise control. Surge would cause turbo boost to jump 1-4 psi each cycle. Regardless of altitude between 3500 - 7000 ft, my symptoms were unchanged.
Vehicle: 2020 Ram 3500, purchased Dec 2020 with HO & AISIN
Dealers: the truck displayed this problem from Day 1. Two dealers told me to just wait for the computer to eventually learn my driving habits. (wrong). After about 10,000 miles, I finally read all the ideas on this forum about the injector connections, the TSB for the CP4 pumps, and checking tranny fluid levels.
Solution: Took it to a 3rd dealer and requested the TSB 18-059-20 flash. Their report says they instead performed TSB 18-012-21 Rev A on June 7 2021. "Updated PCM software 524010032AG-AK". I'm interpreting that is a full software update. Seems to have resolved 95% of the surging problem. The only remaining problem is without a trailer, but with a modest incline (say a 2% grade) at highway speeds. At that situation, most passengers will comment "why is the truck kindof jumping?" But if instead I had a loaded trailer, or are intentionally accelerating, it smooths out and is nearly imperceptible. I have not noticed any obvious degradation in mileage or power after that flash. So, Goose, I am NOT trying to say that the new PCM software improved my fuel economy. It was fantastic from day 1. I'm saying that the PCM upgrade version I received didn't crater it like some other owners reported when trying to address the surging problem.
As I was posting in this thread, I'm still pleased with the mileage. I remain tempted to try to eliminate that last 5% of the surging, but fear it could drop my fuel economy down to what others are observing.
