When I pull my trailer with my 1500 sierra, I get about 8 miles to the gallon. I would really like to get better MPG than that am I am considering getting a diesel. The diesel that I am looking at is a 2006 f350 dully. what kinda MPG do you get with that truck. I am thinking 12-13. Im also considering doing the E3 spark plugs and then doing the K&N airfilter for my current truck. Do you think that will give me what a diesel will or do I just need to see what kind of deal I can get on the 350. And then on the other hand, if I do the k&n and e3 spark plugs with the diesel, I will proab end up getting better MPG either way.