The truck at 3500 miles now and I refilled 7 gallons of DEF so far.
Have no indication when REG occur and driving it for hauling with CC on, I don't feel any power surge, but lately on longer trip I drove it for 150 miles to average 11.2 mpg (with cargo trailer)
Than I fill up and reset the meter. For next 50 miles computer was showing 8.2 mpg.
Same load, same road, same speed WTH?
So after driving 78 miles I fill up again (cheap fuel, that I could not refuse) and after reset - 11.2 mpg again.
My only explanation is that lower mpg was cost by REG cycle that I had no idea was happening.
My calculation is that it took 2 gallons of diesel, but DEF scale did not move from full.