The early built trucks don't have the mds light. Without the light its near impossible to tell when its on.

 

If you don't have the light, your gas pedal will vibrate slightly when MDS is active. I personally was able to tell by the sound alone, even before I removed my resonators. The engine note will change a little. Maybe I'm just sensitive to things like that.

 

I would have to say my MDS never comes on unless it does it seamlessly like it is suppose to. No light .
Now if you are worried about mileage take the truck back to the dealer and beg and plead for them to take it back. If that works I would be amazed LOL. No really you can't expect good mileage from a full size pickup. Unless 15 to 20 mpg is good to you.

 

thanks Guys !!! good to know !

 

I have an October build 09 ram with no fuel saver light and I asked the local dealership to update/scan my software. I told him the issue about the no fuel saver light and if he could get it to come on. He said he would see what he could do. He came back and said under the star scan tool it showed as "Deactive". He upgraded the the software and said thats all he could do and he didnt know why it shows deactive.. Sooo now i'm wondering if the earlier builds actually even go into 4cyl mode or have it? I really cant tell if it does go into a 4cyl mode. I was getting about 19mpg before the software update now i can barely get 15mpg , thats babying the throttle..

 

Did you reset the MPG on the EVIC before you hit the highway?

I recently did a trip to Wash. D.C. and back (approx. 600 miles round trip plus in town driving). I averaged 21.5 mpg on I-95 on the way down, and 19 mpg total for the trip. I averaged about 70mph south bound. Kept the pedal steady, but wasn't afraid to get on it when I had the chance. My truck had less than 2000 miles on it, so it wasn't fully broken in yet.

Laramie Quad with 3.55's.

 

I just put the first 1000 miles on my 1500 Hemi Crew Cab. I've only had it around town and some short interstate trips yet. I'm getting 13.5 mpg to 16 mpg, which I think is pretty good for what are essentially the first two or three tanks of gas. My last truck was a 2005 Hemi 1500 QC. My mileage was consistantly 13 to 15mpg (mainly short trips, city driving) until I got about 7500 miles on the truck. After that I started getting 15 to 17 in town and almost 19 on the highway. Nothing changed with the truck or my driving. I chalk it up to break-in.

These trucks aren't exactly a Prius but then again we have huge vehicles with almost 390 H.P! I'm happy with the mileage.