The code 0304 cleared itself after driving on the highway but I did notice a crack on a plastic vacuum hose, and now my cruise control is acting funny I mean it works but not with the same capacity it once had can this be related to the crack.

 

I'm fairly sure the cruise control is vacuum operated.

 

Alright DF I replaced all my spark plugs on all eight cylynders and finally replaced my 02 sensors (codes been on for a month now) my Durango ran so clean and smooth. I cleared my codes so hopefully that solved all of that. So far no studder at 40 mph. What else could've caused the misfire on cylynder 4?