[V8] ABH using lots of fuel!

[Dag Bøsterud]

My 92 V8 4.2 got the head gaskets replaced and it's heads rebuilt during April 2008.
After this, the fuel consumption has been like.. A Cadillac with a 500 cid V8!

The engine is very smooth during the whole range, fires on every cylinder and performance is not down
as far as I can tell.

I read fault codes and replaced the oxygen sensor just to make sure, although I'm quite sure that's not where the problem is.
The car still runs very rich.

Has anyone got any I as to why the engine suddenly startet to drink fuel?

/Dag
92 V8 4.2
202 000 miles