[Diesel_Dave]

I'll admit right up front that I'm biased. Nevertheless, here's my 2 cents worth.

In my opinion if you after FE you gotta go with diesel. Now, like you say, that will require going to 3/4 ton. I wish one of the manufactures would finally release a 1/2 ton with a diesel like they all said they were going to do a few years ago (Cummins still has a V8 5.6L engine just waiting for somebody to buy). The diesel all have 6+ liter engine so you'll have way more power/torque than you need, but if you learn how to drive it, you can still get good mileage. The diesels are also more expensive, but you get what you pay for. You can also find used ones pretty reasonalby, too. 5 years old can save you about 1/2 the cost of new. And that doesn't really matter much--average time to first overhaul on a good diesel is over 300,000 miles.

Obviously, I'm partial to the Cummins diesel. Both the 5.9 L (2007 & earlier) and the 6.7 L (2007 & later) are very good engines. Although, to get good FE with the 6.7 you pretty much have to get rid of the DPF (diesel particulate filter)--as you would with any of the post 2007 diesels. There's several guys on this site have Cummins diesels. Most of them run mpgs in the low to mid 20's. Since I've started focusing on FE I've been able to get mine up into the high 20's. Last tank was over 30 mpg and this current tank will be better than the last one.

There's a couple Ford diesel guys on this site that have gotten in the high 20's as well.