> Now if your exhaust is coated with a lot of carbon
Very much so. The air fuel ratio gauge was working fine. Now it's hardly
reacting to mixture changes at all. I tried blowing it off with compressed
air with no change.
What's a good way to clean the sensor?

By the way, I used Tracy's EC2 defaults (I got the upgrade at Shady Bend)
and the engine now runs MUCH better. Now for the fine tuning, once I get the
sensor working again.
Regards,
John Slade