I finally got around to checking further into my code 71 CEL this past weekend. Since the EGR valve previously tested fine, I unscrewed the temp sensor to take a look. The end was heavily loaded with carbon, so I cleaned it up. Haven't driven it far enough to find out if the CEL comes back yet. Considering the level of filth on the sensor, I'm wondering if it's likely the EGR pipes are in a similar condition. Has anyone else cleaned up their EGR system?