I have an 06 QC Hemi. I just had my flomaster exhaust installed last week so I can tell when the mds kicks in and it doesnt seem like it is working just right.
Below 45mph- kicks in as soon as I get to steady speed. (this I think is right)
between 45-65mph- kicks in for about 30 seconds and then turns back to all eight cylinders. it repeats this over and over unless you start accellerating or slow down.---also when this happens, my rpms go up byabout 250. when it does this i am on smooth flat surface with and withoutcruise control on.
above 65mph- it doesnt kick on at all.

Is all this normal. Notsure exactly how this system issupposed to work.

Thanks

 

Sounds like you have a bad refibulator valve.....[8D]

 

mine works great at 65 and higher but any slight strain on the motor and it is off