My 06 was doing the same thing before I blew up the motor 2 1/2 years ago, this is a pretty common issue on 2006 rams. You will need to remove the cluster and reflow the solder on a couple chips and it will be good to go. There are videos on youtube that show you which ones and what to do. I have done it on my cluster and it was pretty easy but I have yet to test it since I have to finish my build.
it's both, I had Arrow build the bottom end, I went with the gen 4 head conversion. Flowed the heads and found major reversion at .600 lift and had to port, grind valves to get rid of this. I have some concerns with the bottom and am talking with Prefix(Arrow) to get their take on it.... So far a ton of time and $$$