I bought a used 2014 Odyssey with 70k miles a couple years ago. It ran perfectly until just over 100k the plugs fouled and the engine misfire code came on. The dealer said it needed new piston rings! My old 2004 Odyssey went close to 300k miles and never had that problem. About $2,500 to replace the rings at the dealer. They can take out the pistons without pulling the engine. (Pull heads and oil pan.) They also insist on doing the 100k service (new belt, plugs, and water pump... another $1500). If so... big disappointment. In my younger days I would have done this job myself. Have you experienced this with newer V-6 Honda engines (J35Z8-VCM)?
Besides the issues you already have, the automatic transmission on Odyssey is a weak point too. Maybe it is a good idea to get rid of the car than spending so much money.
I would get a second opinion from an independent, honest mechanic that works on Hondas. Also, unfortunately, that engine J35Z8 has cylinder deactivation (what Honda calls VCM) and can wear out/damage the engine over time including consuming oil. Plus it has a timing belt and not a timing chain, another item to budget for. It’s not a recommended engine for longevity.
We have a 2014 Odyssey with 19k miles no troubles at all... Time will tell.
Those engines have cylinder deactivation so engine problems come from there and the automatic transmission was changed to a new unit in 2014 so that is also a source of problems.
