Sorry...couldn't resist...
My 2.0 and then the 2.3 that I replaced it with...have put several Oil exec children through university...
Your situation sounds a bit different though...as mine would drip oil from all the places that it blew it out...like the dipstick, the valve cover, and the breather (carbed)...
I tried making a catch can and venting as much blow-by as possible...to no avail...
You may be burning a bit without really noticing it due to dispersion...you can't really see a minor burning at road speed and the engine is under less pressure during idle...at the beginning...it could be valve seals or rings...or your PCV valve simply isn't working causing a bit of excess pressure and spitting a bit out...
So...check around the back of the valve cover for leaks and around the dipstick, which drips down the oil pan and can appear to be dripping from any number of places.
Replace the PCV valve is you haven't done so already and take the little hose from the valve cover off the throttle body and check it for oil drips...those go into the combustion and may not be noticeable when burned at speed.
While driving at highway speed, deliberately let off the gas and watch in your passenger mirror for a small puff of smoke...if you have a manual transmission it might show up between shifts also...that indicated valve seals...usually....the high suction (vacuum) as the revs drop allows oil to pass the seals.
Do the same when you first start the truck...if you see smoke then but not afterwards, your valve seals are letting oil drip into the combustion chamber while sitting...
Could be rear main as mentioned above, but there will be a larger and larger pool as the seal breaks down...there is a possible fix in the "Rear Main Seal" concoction put out by Barhds (sp?) that I used at one point...it didn't stop the blow-by that my truck was suffering from...but it helped with compression a bit...
A liter every 700 km isn't too bad...but it will get worse...when it hits a liter every 200 km or less then you are looking at a very near experience with an engine swap or rebuild...
Start planning now if that is the case. And happy hunting...a leak is not as bad as blow-by, but could actually be caused by excess pressure in the oil pan...and that is almost certainly bad rings. The moment I finally fixed the leaky valve cover seal the oil found its way out other openings...mostly the dipstick...but it even squeezed out the belt tension peg that sits behind the belt cover...so I spent quite a bit of time sealing leaks before I realized the real problem was actually bad rings...