My 2006 Dodge Diesel 2500 MegaCab with 139,000 miles started having this vibration every now and then about a month ago. Now it is doing this several times a week. it doesn't do it all the time. driving down the road fine then at highway speed 65mph feels like I am driving on a rough road for a few miles then it stops. no pull in the front end and no loss of power. Just had my fuel and air filters replaced today, started vibrating again after 30 miles.......help!!

 

Have you tried taking it to an alignment shop and let them check the front end and suspension?