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My wife's new 2012 seems to work well. I can hardly tell the difference between on and off. Going down the road, when the ECO light is on, sometimes there is a slight almost vibration, not hardly noticible. Give it any pedal at all, and the power is right there. I'm assuming this has to be saving gas, and it doesn't affect drivability, so whats the problem? The only thing I don't understand is why it doesn't do it at idle, like at stoplights... that seems like a logical place to cut cylinders and save fuel!! Earl ....... PS We love our HEMI'S!!!
 

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The only problem I have with MDS is city driving. Highway it never poses an issue. The problem in the city is that there are numerous times where you have to get on it fast and if the MDS is on you get a bit of a hesitation. It's that hesitation and it's shudder that drives most of us crazy.
 

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MDS and ECO are NOT the same thing!
 

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ECO light is on when you driving economically right? ... and MDS is what my engine is called (actually called 5.7L HEMI MDS VVT ENGINE what my build sheet says anyway) right? I am catching on, or at least I am trying.
 

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MDS is a system that drops the engine down to 4 cylinders while cruising in higher gears. The ECO light will turn on when MDS is on, but MDS is not always on when the ECO light is on.
 

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I had to get rid of mine because if I wanted a 4 cylinder I would have bought a Kia or something. I bought a V8 and I want the power there all the time. I hate the shift feeling while I am driving. My gas mileage did not suffer at all when I got rid of it so getting the DSP was money well spent since I have a few more ponies under the hood, no hessitation, and I can make changes when ever I want to include my tire size to keep my speedometer accurate. I guess it is a choice.
 

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people hate it because some have a hesitation and a vibration, does not work not as advertised. i have no issues with it, and also think it should drop down to 4 cyl when stopped.
 

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It is not seemless as they say. It feels as if it needs a tune up and has no power. When it comes out of mds there is a surge of power. I hate it and try not to drive using it.
 

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I really don't understand why it does not operate at idle while stopped. There are now a number of vehicles that fully shut off the engine while stopped. Seems that if the intent is to save fuel, save it when there is almost no need for almost any power.:4-dontknow:
 

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Don't like how it feels on my truck (hesitation, vibration, wierd exhaust note) but I'm giving it a try to see if it improves mileage at all.
 

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Are we assuming because the Eco light goes off when stopped its running on 8 cylinders? Any one know of any technical articles explaining how it works?
 

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I've had the MDS in an '05 C, and '05 WK and now on my Ram. Have no complaints whatsoever. On all three vehicles I never could tell when it moved back and forth between 4 and 8.
 

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Just speculation on my behalf, but I would expect the engine to have a very irritating idle in the 4-cyl mode. Look at all the complaints of MDS roughness while the engine is actually under power, and you could imagine what the feedback might be if MDS was engaged at idle.
 

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At 40 mph my rpms run about 1100/1200. This speed is the WORST and can't stand the vibration! I live in florida by the way so I feel the vibration forever if I'm on cruise control. The computer doesn't need to adjust to speed or anything because its flat the whole time, so this vibration can last for miles at 40ish mph
 
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