Yeah, Hemi's have a tendency to get excited when they know they're going to the gas station.

 

 

its been -25 to-35C (-13 to -31F) the last few weeks and my hemi starts and runs fine, dosen't matter if it warms up for 30 sec or 10 mins so diffidently something wrong

and ya my hemi also like to chug gas in the winter lol

 

So driving home tonight: truck started and ran fine BUT on highway doing between 65 and 70 the truck would seem to shift almost. RPMS jump from 1800 to 2000, kinda abruptly and then stay there and come back down. I tried maintaining speed and it would do it every so often. I think I have a tranny issue somewhere. I dont know, is this the MDS kicking in and out going up and down hills? BTW, truck didnt do anything drastic lately like the other day. It starts and the engine seems to sound perfect and shifts fine going from through the gears. HELP!!! Truck is fully under warranty from Dodge, so I wanna know if this is an issue or just how the drive. I havent owned a pickup b4, only larger SUV's

 

If the original issue happened once and not again then I would not worry about it.

As for the jump at 65-70, sounds like MDS to me. Going up and down hills and doing it? Most certainly MDS. The truck simply needs more power to climb hills and hard to make a 6000# truck do that one 4 cylinders.

You sound fine to me. Try getting a Superchips 3865 and disabling the MDS and see how you like it then.

 

I agree with Weed. The only other possibility I can think of, making a 200 RPM change, would be the torque converter locking and unlocking, due to extreme cold outside temperatures. If it still does it after the truck has been driven for 20 Min. or so, I don't think that would be the case.

 

Hey,

Thanks SOO much!!! Was really freaking out that the tranny was slipping or something. I thought maybe the MDS would do that and it totally makes sense bc it isnt jumping like 500 rpms, its a suttle difference adding more power to the truck. other than these two things, I lOVE this thing. Cant wait to get it up to Maine next month and play in some real snow. Any advice on add ons to get a little better fuel? 14mpg hghway sucks! It has a flowmaster i think 40? Came with it so I didnt do it, brand new tires, so its got a few things. I am running 92 in it. I am thinking an K and N filter? Any other suggestions?

Ben

 

Nothing that will make any real difference, it seems it's easy to get better performance out of the Hemi, but tough to make any headway on economy, a tuner might give you 1-2 MPG highway, but much better drivability.