Intro to Variable Cylinder Management Technology
The 2005-2007 Honda 3.5L V6 is a VCM-1 engine and only does cylinder deactivation on cylinders 1-3 instead of 1-4 like the VCM-2 engine. The 2005-2007 Honda 3.5L V6 shows misfire and oil consumption issues at higher mileages in most cases because only 1/2 of the cylinders can be used in these model years during cylinder deactivation. Above the 100k mile range is usually when oil consumption and misfire issues begin on this version of engine from wear over time.
In 2008, vehicles with VCM-2 engines showed high oil consumption as early as 10k miles due to aggressive programming in the where up to 4 cylinders were in cylinder deactivation mode; leading to the engine misfire settlement in 2013/2014.
Many mechanics who have worked and rebuilt these engines speculate that during cylinder deactivation, the engine vacuum starves the cylinders of adequate lubrication while in shutdown - reduced oil and lubrication while vcm deactivation is occuring. Additionally, spark plugs show discoloration from a mixture of uncombusted fuel and oil mixing in those cylinders which can cause micro-abrasions on the cylinder walls over time leading to a loss of cylinder compression and oil consumption and the fouling of spark plugs and eventually misfire codes (e.g. P0301, P0302, P0303, P0304).
Some vehicle manufacturers like chrysler who utilize a similar system called MDS have a timer/counter (only a few minutes as seen on early 5.7L MDS enabled engines) on how long the cylinder deactivation can take place to minimize the damage from cylinder deactivation technology and do a better job at re-lubricating the cylinders with shorter cylinder deactivation intervals.
Internal testing shows that cylinder deactivation on a long downhill slope stays engaged for intervals up to 10 minutes at a time and is likely the root cause of a loss of cylinder compression. From our research, study of honda's own patents on VCM technology do not specify a maximum amount of time where the cylinder deactivation can be engaged to minimize lubrication losses.
Honda's own TSB linked below details honda's attempt at reducing how often VCM is engaged during light loads to reduce oil consumption; however even with these improvements the documents state it only 'may' reduce oil consumption and does not guarantee this change will resolve the problem going forward.
2013 Lawsuit Notice
2013 Lawsuit Order by Judge
Video Documenting 2.25 quarts of oil consumption on a brand new Honda Odyssey
Video Describing VCM Vibration Issues by Honda