My 1998 Toyota Camry check engine light is on. The code is EGR valve, insufficient flow. First I removed the valve and cleaned it with Seafoam deep creep. Reinstalled, disconnected the battery. Check engine light stayed off 3 miles. Removed again, cleaned again, this time removed a hose that was completely choked w/carbon. Cleaned it. Reinstalled. Check engine light came back on after 15 miles (but the car runs much better!) Bought a new EGR valve. Installed. Check engine light came back on after 10 miles. The car has 281,000 miles on it. It runs fine & is in fair condition, but I don't think it's worth dumping a lot of $ into to fix. I would like to be able to sell it as a car that will pass an emmission test, though. Is there anything else that could cause the "insufficient flow" error? Any advice is appreciated.