I've has numerous issues with my 2007.5 RAM with 6.7L engine after I first purchased it. Virtually all issues had to do with the emissions equipment. Some of the issues have been resolved through computer updates and other procedures. I'll still get a "nuisance" CEL now and then but the truck has never let me down to the point I couldn't use it. I'm a little peeved that the dealer never mentioned these trucks aren't meant to be daily drivers (IOW, used like a regular gas vehicle around town). That being said, if you use the truck the way it was designed (for towing and not as a grocery getter) it will have less problems.
Oh, let me add that a code reader will be your friend. They're easy to use and will tell you what the CEL means. They can be purchased at Walmart for reasonable cost. It's also good to know what the problem really is before you have a dealer mechanic look at the vehicle.
