Why is my 97 model ford courier using so much fuel?

Question

I have changed;
*Fuel filter
*Air Cleaner
*O2 Sensor
*Injectors
*I have had a code test done with a scanning tool
*I have used injector and carb cleaners, everything
I can not think of what would be causing me to use so much fuel. No one seems to know!
When sitting at lights in drive it idles a bit low, but timing is what it should be according to the manual. Place the car in neutral and idles fine. Have not lost any noticeable power.
Can anyone help me? I am only getting about 250-300 km to a tank ):

Answer 1

Put it on a dyno tuning machine, check the vacum advance hose it may be old or cracked. Re-check timing and ensure the idle is set correctly by someone who knows fords, as they are a bit tricky to get right but once u do they should stay that way and adjust accordingly in relation to driving conditions

Answer 2

Is it an automatic or manual transmission? Automatic transmissions have an overdrive. If the engine doesn't reach the proper operating temp. the transmission won't go into overdrive on some models. What happens is the computer goes into closed loop when it reaches operating temp. If the thermostat is stuck open or missing it will stay in open loop and therefore won't use overdrive causing low fuel mileage. Hope this helps.
Master tech 40 yrs.

Answer 3

Jesus Christ have u got a hole in the tank or something. the old sierra engines used to be horrible fir fuel consumption but if you have done all that it may be more serious if i were u i would chop it in for a tdi caddy much better on the juice.

Answer 4

A clogged cat will do that.