Im new to the forums, so hello. I bought a 2010 reg cab ram hemi 2 weeks ago. I notice at around 40 or 45 mph when i coast in that range, my truck sometimes will sound rough and vibrate a little. When i speed up or down it goes away. I called my local dealer and he said he didnt know what it could be and that no one else has ctold him of that problem. I wanting to know if some of you guys are having the same problem or might know what the problem is. Thanks

 

It's probably the MDS, when you're in 4 cylinder mode it sounds and feels a bit harsh, like a vibration

 

i thought the mds was suppose to be out on the highway when you were in cruise. its kinda weird it does it at 45 isnt it.

 

No it does it all the time. Whenever there is a light load on the engine it will engage.

 

I hope you are right. The truck is under warranty so im not to worried about it. Its a sound like the back window is rattling a little bit. Its kind of embarrassing when you are showing the truck off to a friend and they are like what the hell is that.

 

Its the MDS kicking in. Mine does the same thing as well. I can feel just a minor vibration when it kicks in.

 

Are your windows open at 45?

 

Does your mds light come on when it happens, if not its something else.

 

Not neccessarily. There is an option to turn off the fuel saver light in the EVIC

 

really????
then check to see if it is active and on at 45