Ive had my 2008 1500 Bighorn for about 2 months now. I bought it used with 10,076 miles on. it had a few dents, which they fixed for me as part of the deal, but other then that it seemed like a solid truck. i got it for 25k. i wanted a 2500 CTD, but i couldnt find one in my price range around here. so i bought this truck. over the past few weeks, ive been noticing at between 20-50mph, the engine rpms drop and the motor sounds like its really *******. i have dual flowmasters on it and it sounds extremely deep. but when i push on the gas a little it seems to come back to life and the rpms raise back up and there is a big difference in the sound. is it the MDS kicking in when it shouldnt? i took a trip this weekend, about 400 miles roundtrip, to va. when i was heading down the interstate, i had to really get on it to pass a truck and i noticed that the truck seemed to jump a little bit during acceleration at the higher rpm's. when i had it on cruise, the motor would slip back and fourth between gears... but maybe that was just the MDS kicking in and out again. i averaged about 20mpg on the way back. maybe im just paranoid, but something doesnt seem right. ive towed with it a few times, and only heavy once. the bed is scratched to hell, so who knows what the previous owner had down to it.

 

Is you A/C on while you are experiencing the symptoms?

My 4.7L (2008/RAM1500/<20K miles) is acting (RPMs that is) like yo-yo when doing abt 30mph (with A/C), while RPM is just north of 1,000+

K

 

yeah it does sound like the MDS, I have an 06 1500 but I haven't had any power problems

 

it happens with or w/o the AC on. its been great for the gas mileage on the highway. ive been getting between 18-20mpg on long drives, but it seems pointless around town and seems like its doing more harm then good. when its cold(even after running a few minutes) it hesitates during acceleration. im gona take it tomorrow to get it looked at. ive been having trouble with my turn signals, so ive gota go there anyway. the truck has 13.5k miles on it now btw.

 

That totally sounds like MDS, try driving with the "tow/haulass" button pressed that should take off the MDS and if it fixes your problem then pick up a tuner and be done with it.

 

well, i tried driving with the switch turned on tow/haul and it seemed to fix it over the weekend but wasnt sure if it was ok for the tranny or not, so i turned it back off. what kinda turner are you talkin about? ive been looking for parts for the truck, but cant find any good websites. any suggestions?

 

It's just fine for the trans, as for tuner you can go either the superchips flashpaq or the diablosports predator. I'm 100% positive the DS predator has the "MDS disable" in the menu, and gives a little more power, because I have one on my truck. I'm 90% sure the superchips can disable MDS as well but I have no experience with it. Your best bet is to do some searching on here and read up on both.

 

yup..the tow/haul locks out mds...I don't have mds but i city drive religiously with tow/haul on and only taking it off for highways.. and like Hoss says, diablo and the new superchips have the mds disable feature..

 

ok sweet. im gona take it to the dealer and still have it looked at when i get a chance. it did it again today and it felt like the transmission was a little jumpy. its still under the 36k/36month warranty.

 

I also bet a symptom of it is your exaust, rather than 20-50 mph mine is at 40-60, I figure the lt headers no cats an tru dual exaust I lost some torque wich tends to make my trick mushy an sluggish well I drove my friends exact truck 05 qc hemi wich has stock exaust an has no prob accelerating at any mph. So I blame exaust.
This statement is just about your lower mph an not on the highway I have no experience with mds. I believe new gears and a cam will solve my prob with the mush. Either that or constrict the exaust a lil more wich won't happen.