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The defining Honda J-series VCM defect is an oil-consumption / spark-plug-fouling chain: when Variable Cylinder Management deactivates the rear bank to save fuel, oil slips past the rings on the idle cylinders, pools on and fouls the rear spark plugs, and eventually triggers cylinder-specific misfires (P0301/P0302/P0303), a shaking engine, and a blinking check-engine light -- owners report loss of power merging onto highways, and in the worst cases piston-ring or engine replacement. 377 federal ENGINE complaints across the 2011-2017 Odyssey and 2009-2015 Pilot (both V6-only, so unambiguously this engine) and the V6 2008-2017 Accord describe oil consumption, fouled plugs, or VCM misfires. Honda has never recalled this; it has been fought as warranty and class-action matter, and many owners fit an aftermarket VCM disabler.

Check — Ask how often spark plugs and ignition coils have been replaced and how much oil the engine uses between changes -- more than about a quart per 1,000 miles is a red flag. Pull the dipstick, look for a low or fouled reading, and scan for stored or pending misfire codes on the rear (firewall-side) bank. Repeated plug/coil replacement is the tell that VCM oil fouling is active.