I am the proud owner of a '03 4.8GRX, what a car..... but the fuel burn, eish..


Most of the travelling is long distance and sometimes with a trailer
The advertised fuel burn on the side is expected but I don't even get that, and, no, I do not have a heavy foot. Travelling is at a very sedate 100-110km/h
4.2-4.5km/l is the norm
Can somebody give some advise and not driving it is not an option
I bought it from a Nissan dealer, not necessary a good thing, she has 200k on the clock, Burnco bumpers front and back, snorkel, 33' tyres, Ironman suspension
Any suggestion would be appreciated