Hello.

First post on this forum.

While I have owned the same 40' diesel motorhome since 1995 (300 Cummins), the only thing I ever did to it was fluids and filters it never needed anything else. So my diesel knowledge is generic and limited.

I have always turned my own wrenches on everything from the wheelbarrow to our airplane.

I recently purchased a 2008 Dodge Megacab, 4x4, 6.7. It has 285k miles (zero blow-by) and a rebuilt tranny 70k miles ago.

On our 500 mile trip bringing the truck home, I averaged 18 MPG at a 75 MPH average speed.

Not bad, but was hoping for the 24 the seller touted.

Turns out his MPG figures were coming from the overhead display (certainly not realistic)!

The truck has an MM3 tuner to which I am trying to sort out since this is outside of my knowledge base.

We are teaching an old dog new tricks! ....slowly...

That said...I am not interested in crazy HP and such, but rather MPG and solid performance.

While my right foot has great control, I don't mind using it, but again, not into hot-rodding.

I have no documentation on the MM3. So how do I determine who did the tunes for it and what the HP/parameters are for them? I would like to know what I have! My plan for this truck is to pull a 4,000 camper.

I have been reading everything I can find on the MM3 and while my knowledge is increasing and there is still so much I don't understand, but I'm working on that!

Thanks for allowing me to be part of this forum and I have been enjoying reading through the endless posts and information!

Appreciated!