I've only had one oil in the Toyota that was consumed. I noticed it in just 400 miles. First thing that came to mind was the PCV valve. When I checked it everything seemed ok. But it had been several years since I changed it. I had one and just swapped in the new one. My oil usage dropped back to what had been the norm for this car and it used about a hair over a cup for the rest of the OCI. I've heard of this problem but have never personally experienced it. YMMV.