Gu patrol petrol 4500

Only if the old ones are faulty or out of spec. What is your current fuel consumption?

About 18 to 100

Just back from 6mths 25k km in4.2 diesel gu. If pumps fine leave it. We got about 15l 100km can give exact if want. Was pushing gvm on departure. Best fuel reduction was lighter aerodynamic and slower. Bot in that order. The diff btw 100 and 90kph is significant and saved time irrelevant.

I agree with nickb, only if faulty or o2 is out of spec. You would need a tech device to read it’s small voltage output to the ecu to check. I remember you had trouble and suggested a valve clearance check because that makes the intake and exhaust gasses in synch with each other and will have a beneficial effect if all correct. Ensuring the ignition timing is set to the fuel to be used is also good. A new fuel pump is a sound thing to carry as a spare but if the original is working properly then it has not bearing on consumption.
The fuel injectors may be spraying squirts moreso than a fine spray. Possibly a dose of injector cleaner may assist in restoring their performance.
I replaced the head on one a year ago, but can’t remember what the front pulley is like. If the front pulley on this can move it’s outer rim and timing has been done to that instead of the actual piston position, then it may be running retarded although a normal timing check says it is correct. You need an informed mechanic to make sure all is well there.