Has anyone had issues with the MDS system. My 05 300C runs rough at constant throttle but when you ever so slightly increase throttle, it smoths out. Happens at 30 mph through 70 mph. Thinking it may be an issue with cylinder deactivation. Thoughts? Thank you in advance. PS engine will sometimes die at idle. Won't start with foot off throttle but takes right off when you put a little throttle to it. Still turns over, just won't start. Does it a coupld of times and then is fine for another month. No check engine or codes that I am aware of.