Scotty, My well maintained, one owner, bought new 2003 Odyssey with 190k miles has lost compression in one cylinder (codes 301,302,303) I've verified this with a compression gauge. The traction control light is on and the check engine light is flashing. With used car prices through the roof right now, is it worth it to open the top end and repair?
It could be bad valves or piston rings. Do a leak down test to isolate the problem. If it's bad valves, I'd pull the head and have it re-built and reinstalled. If it's piston rings, I'd sell it for what I could get and move on.
On the small chance that the rings are stuck, you could try pouring MMO or some other gunk down there, and soaking it. Then rev it up to 5k for a while and see if that frees up the rings.
Or if you can get your hands on a boroscope, you can check the cylinder walls for damage.
If that doesn't work, then ...
I would junk the car. It's not worth the repair.
