i have a dakota 4cyl and a half tank only gets me about 70-80 miles is that correct???

 

11 gallons is way too much gas for only 70-80 miles. When did you get the truck? What do you know about it?

 

has 94k miles runs smooth got 5 months ago

 

Welcome to the forum Uriah.

What year is it? Do you have any codes? What color is the tailpipe?

To calculate the MPG, fill the tank then drive it. Next time, fill it up again., How many gallons did it take and how many miles did you drive?

Using the gauge to calculate mileage is very inaccurate, it's not linear.

 

its a 98

 

But 00DakDan, that makes too much sense, and is the totally obvious way to do it.....

 

The 2.5 will give you 18 to 21 MPG its not that great on MPG for a 4 why its a Truck all Trucks have poor MPG they are Trucks

The Gas tank in the 2.5 is a 12 gallon tank many say its a 15 Gal tank but I have a spec sheet from the factory that says 12 and I have only been able to put 12 gal in my tank at most that's bone dry.

He may have the 15 its possible

From my sheet

Fuel Tank
Fuel Tank Capacity, Approx. (gal): 12

Mileage
EPA Fuel Economy Est. - City (MPG): 20, Est. - Hwy (MPG): 25

 

If you want a little more Zip in the 2.5 swap the 2.5 throttle body with the 4.0 throttle body

It will not eat more Gas just pep it up some

Some links

http://www.4x4wire.com/jeep/tech/engine/throttlebody01/

http://www.links4jeeps.com/forum/index.php?topic=9371.0

Just remember to swap the Idle chamber and IAC from the 2.5 onto the 4.0 or your Idle will not work so good on you just cut the key off the Idle chamber you will need the proper keyed torx bit to remove it.

You could try this a 62mm one http://www.ebay.com/itm/Jeep-62mm-63mm-4-0L-2-5L-1991-04-Ported-Throttle-Body-/370322497378?pt=Motors_Car_Truck_Parts_Accessories&hash=item5638f0df62&vxp=mtr


I want to get it some day just to see if it helps

Be sure you get a 4.0 with the MAP sensor the other one will not work with the Dakota it needs the MAP sensor

 

Install a new TPS and MAP if you have the $$ be sure the air temp sensor is good and clean or a new one also

Don't lose the little MAP sensor elbow or break it

 

Dakotas came with a 15 or 22 gal tank. So find out which one you have(im guessing 15 gal)

If you have 15 gal and use half(7.5 gal) at 70miles thats like 9mpg and 10mpg at 80miles. Tho you cant get a true mpg reading unless you run it till the gas light comes on.
Lots of factors here.
Are you auto or manual?
4x2 or 4x4?
Do you drive in stop and go or highway?
Ever done a tune up on the truck(plugs,wires, rotor and cap)
Hows your brakes(dragging will cause a drop in mpg)
Clean air filter?