I have the same in my Surf but there are other factors to consider
George is correct and engine comes up as UZZ31 Soarer or as no frame no is provided UZZ30 SC400. Checking the Surf I have the same ECU and AFM. And my engine was from a half cut so I kept the tag to have the frame number handy for future reference
Now things that will cause it to eat fuel.
Diff gearing and tyre size does play a big part here. You ideally want 4.3 diffs on 31inch feet a then the engine spins at 2600 @ 100kph with R150 box.
Exhaust. Crown type logs strangle the damn thing. I now fit custom extractors with single system. Extractors based on conversion form diesel available from here
http://mufflerbrake.com.au/ But be aware they are based on my vehicle yet fit most. My engine sits in the same position as the original 2L-TE on its original engine mounts rubbers with no mods to the chassis
O2 sensors. These run a single wire main O2 and the Sub as such is only a "Heat warning" for the cat so lack of which doesn't worry them. New O2s and ignition coils will help a lot as will replacing the coolant temp sensor. These have a cold start injector so if that sensor aint working properly you're in effect driving around with the choke on.
Lastly aside from how you've wired her up.. Air intake, How have you done that? They don't like any form of restriction.
A code check is in order but if you're getting around 3-350km out of a stock Hilux tank before refueling on say 95ULP depending on how far you bury the right foot that' about right. If she has a code in her she will eat fuel like no tomorrow having gone into "limp mode" which shows with a high idle speed