I bought a used 2011 Silverado 3500HD Duramax DRW with 42,000 miles on it, with a Bigfoot TC on top. Unfortunately I've been having a plethora of niggling problems with it.
I was getting 13.5-13.8 mpg depending on whether I'm pulling my 16' x 7' cargo trailer. However, of late the avg mpg indicator has been erratic between 7.5mph and 12mpg. The dealer cannot identify any problem, but I strongly suspect the lower numbers are real based on the actual rate of fuel consumption.
I've also had to replace all the O2 sensors and DEF tank sensors.
After replacing the above sensors was then getting spurious warnings about low DEF range when I know the tank was recently filled. Not fun when you're 40 miles down Hole-in-the-Rock Road. Had to drive 300 miles r/t to a dealer in St George, UT who had to reprogram my computer.
I've been traveling in the deserted Four Corners region, so these kinds of problems have been a royal PITA. I hope these problems are resolved soon. Practically every service manager I've dealt with grumbles about the problems with the DEF systems on these trucks. I'm not sure diesel is worth the hassle....and I'm a machinery engineer by profession.
