Improving fuel mileage on a 1991 Nissan D21

[suttonro]

I am looking for any ideas anyone else might have on ways to improve the fuel mileage on my 91 Nissan D21. I'm not sure what the original mileage for the truck is supposed to be, but it has only ever gotten as good as 15 mpg.

[Rev_D21]

4 or 6 cylinder? Auto or stick?

[Bubba1]

I am looking for any ideas anyone else might have on ways to improve the fuel mileage on my 91 Nissan D21. I'm not sure what the original mileage for the truck is supposed to be, but it has only ever gotten as good as 15 mpg.

15 mpg within 5 mpg of its EPA estimate. Those old hardbodies were more known for their utility than their high gas mileage.

Altering your driving style ( using hypermiler tricks) will give you the biggest improvements by far, but there are a few things you can do to the truck itself that will give you some minor improvement. whether they are worth the cost or sacrifice to the driving is up to you. I assume your filters are all clean and the motor is in good tune, and most importantly your tires are properly inflated.

For example a tonneau cover: You'll hear a lotta hype about big gains, but from what I read you're talking about maybe a .5 mpg improvement at highway speeds.

Keep the tailgate up (Mythbusters proved keeping it down does not help)

empty any unnecessary stuff from inside or the bed.

switch to lower rolling resistence tires. run a slightly higher tire pressure

If the truck is lifted, return it to standard height.

Add an airdam (reduces air flow under the truck)

If you have oversized mirrors, return them to stock, and consider removing the passenger side mirror


Hope that helps.

[Looneybomber]

20yr old truck. Not a lot you can do to it to get better mileage other than change the way you drive.

If you check my sig, I get pretty good mileage for an explorer with 265/75's, albiet nothing to write home about, and I only do basic hypermilage stuff, i.e. keeping tire pressure where it should be (not over inflated though), coasting to stops, not running cruise on hilly roads (meaning I slow down going up hill), don't go much over 55mph even on 75mph interstates. That also means I may take some different routes than I normally would.

If you want to get crazy with it, you can start shutting your truck off as you come to stops and at red lights, draft behind everything you can, and never drive uphill.