I searched for this so please do not flame me for asking.

At what RPM does the engine turn on/off the 4 cylinders?

Is it recommended to put inyector cleaner every now and then? Will it mess with the MDS?

My neighbor has a Hemi truck and he told me that the truck Hemi turns off the cylinders only before 4000 RPM, for me that sounded a bit high, hence the queston

 

I don't really think it's so much a specific RPM as it is a combo of things. Like speed, gears etc. Injector cleaner would have nothing to do with MDS as it is run via the lifters. I can get the MDS in my car to kick just crusing on a flat road at 50 or so...I can tell by the exhaust sound, it gets inda tinny if you will. But I do love the MDS as it makes the MPG n the highway pretty good.

Also running the specific weight of oil is required to keep the MDS system running correctly. 5w-20 is required, anything over that and the MDS system will not function

Hope it helps some

 

Husker is right, when MDS kicks in is a complex combination of many factors, not RPM.

Bob