I think 06 has MDS, my 05 Magnum did the what sounds similar when I put a Diablosport tuner on it. Turns out the MDS throws a fit and is all out of whack. All I had to do was unhook the battery to clear the adaptive learning and it was fine, the MDS was then able to "relearn" within the parameters of the Diablosporttune. It doesn't sound like you have a tuner but maybe something is up with your MDS, maybe one of the soleloids is acting up