I am trying to improve the MPG in my Dakota and I wonder if there is any oil out there that can make a noticeable improvement MPG? It's a V6 3.9 liter engine, manual 5 speed transmission and I have owned it since 42,000 miles. From 42K to 65K I used Valvoline conventional. At 65K I changed over to Maxlife and recently did a couple of OC's with Napa brand HM, all were/are 10W30. I just wonder if anyone else has had any real MPG gain from changing to other brands and/or weights?