Somewhere in the late 90s/early 2000s the 3.9 was replaced with a 3.7. The 3.7 & the 4.7 are of the same design with the same issues, from what Ive read.

A 3.9 works on a standard cab truck caring lighter loads. If you load up your truck or need more then a standard cab, the 3.9 will be under powered and the gas mileage will be worse then a 5.2 or 5.9.

A 5.9 is a bit harder on gas then a 5.2, but its a lot more fun. Either in a Dakota would make a great work truck. Like said earlier, lower miles, best upkeep will get you a better truck. Make sure the bottom is not rusty.

Once past 2001 or 2002, the Dakota started putting on a lot of weight and grew in size. If your after a newer truck, a full sized truck might be a better buy. The original design of the Dakota was a great size, but unfortunately, as the years progressed, they moved farther and farther from the original design until there really wasn't much difference in size, options, or price between it and its full size brother. Gene