i have a ford ranger 2001 edge 4x4 with a 4.0 ,my fuel mileage is bad im getting between 10 to 12 mpg the truck starts and runs great but when i take off i get a little spark knock ,ive been told that i need to have the injectors cleaned any other suggestions would be helpful thanks

 

How many miles on the buggy?

What were you getting?

Have you made any mechanical changes like larger tires, cold air intake setup?

Have you replace plugs, wires, fuel filter, air filter, clean the MAF/ACT sensors, run any type of injector cleaner with your fuel?

 

the air filter is new,the fuel filter is new,the tires are mew and i think they are oversize lt265/75 r16 it has 132000 on it ive run injector cleaner in the tank ,i havent changed the plugs and wires yet but will soon no changes yet

 

Do you generally purchase your fuel from the same place every time you fill up? If so try changing where you're getting your fuel from. I have a 2000 Explorer XLT 4X4 and have noticed that my fuel mileage is a direct reflection of where I purchase the fuel. I used to buy from Sheetz and was getting between 10.5 and 11 MPG. I switched up and started buying from Circle K (formerly Holland Oil) and now I am getting 19 MPG.

 

Funny thing I was just talking about this, cant understand how one place I get more milage than others, any thoughts on this subject.

 

There are differences from one brand of gas to another. For whatever reasons, some engines run good one a certain brand of gas and other engines run poorly.
To answer the original question, another reason for your bad gas milage could be the temperature. Its cold right now and usually the colder the temps are, the worse the gas milage.
It could also be that you have a brake that is dragging or a wheel bearing that is going bad. Either of those could greatly increasing the truck's rolling resistance and lower the fuel economy.