I have a 2005 awd auto that I absolutely love. I will likely have it for another 10+ years regardless what happens. On that note, I have a dirt bike I pull on a small trailer. My ok 21mpg average unloaded tanks to about 12-13. I know a trailer reduces mpg but this is a bit much for me. Within an overall budget of $1,000 to put into it I really want to explore options but can’t find much. Aside from the basics i.e tires air filter and fluids, what can I do for 5ish-mpg increase? Is there a performance tune I’m having trouble finding?