2003 Mazda B3000 Standard cab 2 wheel drive Automatic 3.0
I'm wondering what can be done to improve gas mileage. Plugs and wires are new. I have had the truck for the past 4 years and 18-19 mpg is about the best.
I know the transmission is only a 4 speed Auto. Can a different Transmission be an option? Rear end gear? I know at 70 MPH I'm looking at 2800-3000 rpm.

I plan on keeping the truck for awhile, I'm just wondering is better gas mileage can be achieved.

 

Tires at proper inflation or maybe an extra 2 psi will be your best bet.

Next time you need tires, look at low rolling resistance tire. The higher cost of them may take a few years to pay for them selves, if ever.

Changing to a different transmission or rear end gears is usually not worth it.
Let's say you get an extra 2 mpg, 40 miles per tank, a savings of $5 per tank, $1000 to re-gear or transmission, it will take 200 tanks of gas to break even, at a tank a week will take 4 years.


At 70 mph, a truck is not going to be getting very good gas mileage, keeping it under 60 can save you 1 or 2 mpg.

 

+1 ^^^^

The 3.0l Vulcan engine was designed in the early-1980's first made and used in 1986 so thats the technology it is using

And it is in a truck, the worst design for MPG there is, because aerodynamically its a Brick, and actually worse than a brick because it sits up high and the under side is not smooth like a brick, it has all kinds of holes to trap air flow and create drag, the enemy of MPG

If you can get 18/19 MPG in a Ranger V6 then you are at about the limit of stock design
An e-fan conversion would add a bit more power and better MPG, but as far as pay back on investment it would be awhile
If you lowered it(and I mean DOWN to the ground like a car) and used skinnier tires you might squeeze out a bit more

The new 4cyl 2019/20 Ranger is putting up OK numbers for a truck, not great but OK

 

all good points. thanks for your thoughts

 

And what may really ruffle your feathers, it does mine, lol, gasoline engines are only 25% efficient, 25%!!!

That means 75% of what you pay for a gallon of gas goes to heating the air and up in smoke

So if a gallon of gas is $2, 50cents pushes you down the road, $1.50 just heats up the air and coolant

Some newer gasoline engines are pushing close to 30%

Diesels do 30% and newer ones closer to 40%

Electric cars are about 75% some closer to 80%, so you still have some heat loss

 

That mileage is what I am getting on mine also (same as yours 2wd, 2003 3.0 auto) and after replacing O2 sensors I now get 19.5MPG mainly highway driving so you're in good company. The reasons listed above are true, it's not the best mileage truck around but for me at 245K miles it still serves me well and I can't afford to replace it.

 

What RodD said an efan is probably your best bet. Emissions laws make it so it is in car manufacturers best interest to make their cars efficient so there’s not much easy fixes you can do to your car to help it’s gas mileage as they were designed to run about as efficient as they can. Only reason they didn’t use e fans in the first place is because they are more expensive.