96 Disco we will be using a a ranch truck
do not want to replace
can they be removed and computer and motor work

 

you will get bad gas mileage and alot of heat.

if they are not bad then leave them in.

 

No, your ECU will go to open loop and you'll run full rich and loose power.

 

If you're using it strictly off-road, you might want to consider simplifying by converting to a carburetor.
A number of people have done it and report fewer issues and better mileage, though for a ranch truck I don't suppose mileage matters that much.

 

How do you change to a carb