spark plug is fouled--cylinder may be compromised

Hello, I would suggest a compression test and leak down test for the engine to see if you have signs of internal engine concerns. Further, I would reach out to your Honda dealership. There is a service bulletin regarding excessive oil consumption on this vehicle. They will likely want to start an oil consumption test -- starting with a Honda oil and filter change. You'll need to pay for this to start with, but if your vehicle is using more than one quart every 1,000 miles, Honda will replace your pistons, rings and spark plugs at no charge. This program lasts 8 years from the original "in service" date, with no mileage limit. Naturally, this kind of repair will not happen before your "long, long trip" -- because the oil consumption test itself will take time to determine if your engine has an internal issue that Honda can help out with. However, I can tell you from where I sit: I would bend over backwards to help a client in your shoes managing my Honda parts and service operation...so...I imagine other dealerships will want to act the same. Good luck!