OK, so I'm aware this is an age old discussion, but I'm trying to get better fuel economy from my R33 and wonder what I'm missing here.
Firstly, engine mods are - full exhaust, Blitz panel filter
I was getting around 330kms/tank and decided this was pretty poor. I then replaced the O2 sensor on the assumption that it should have been old enough to be not working at its prime. This gained me only about 30 extra kms/tank.
Now at 360kms/ tank I have recently added a bigger dump pipe and metal cat, making it a full modified exhaust which has not really changed things (that's not why I installed them, though).
The AFM I would have cleaned about 10,000kms ago and I would have thrown in a can of quality injector cleaner for good measure about 5000kms ago, so while I will do these again soon I don't expect much/any change. Spark plugs are around 12,000?kms old, and would have been platinum/iridium?
So the big questions are
1- What OEM parts should I change/maintain to bring fuel economy back up to what it would have been designed to give me?
2- What else can I do to improve this?
Thanks