I also have a Dodge truck, a 2001 Dakota with almost 130,000 on it now. I have a 3.9 V6 though. I don't always run MMO in the oil, the last couple of times I just added it about 500 miles prior to my next oil change.
I am about 700 miles shy of my next oil change now so I added 18 ounces MMO to the crankcase today. I would normally just use half a quart but the bottle had a little more than that in it.
I went running errands around town today after adding the MMO and all I can say is my engine runs really smooth when I add the MMO. Cold starts are not an issue now that hot weather is here again but the engine starts right up in a split second, just a blip of the ignition key. My engine runs very smooth and quiet and has more power, and just plain has more get up and go when I use MMO in the oil. I can tell a big difference when I go up a hill. My truck runs great and still has a smooth quiet idle and good power when I run only oil in it from the beginning of an OCI too. I only have a 4 quart sump anyway, so that is why I don't run MMO for the full length of the OCI, plus with hot weather here now I don't think it's necessary.
I have been using it in my gas for the last 4 or 5 months too, and I get the same smooth running and nice even idle, increased power and 1.5 to 2 MPG increase with MMO at roughly 2.5 ounces to each 10 gallons of fuel.
I mentioned MMO on another forum 2 days ago and they really threw me under the bus about it. I would bet the folks on that other forum probably never tried MMO, and probably never will. But my only complaint is I wish I had discovered MMO much sooner.
MMO is a great product, especially for the price.