Vehicle fouling spark plugs about every 3-6 month due to oil getting into the cylinder(s) causing shuttering, loss of power and stalling. in my case it's my 3 back cylinders. have not brought to honda due to being a ase mechanic myself. started happening at about 80'000 miles in 2018 and has happened 4 times since happening progressively faster. honda tech friend of mine said he's done a lot of these replacing piston rings at the dealer he works at.