A CO meter seems to be a very useful tool that is priced out of the range of
anyone that's not a professional mechanic. Nighthawk makes a CO alarm that
displays CO in parts-per-million for less than $50. I wonder if there is any
way to use this as a CO meter? The main problem I see is with the CO sensor.
I'm sure the Nighthawk sensor would not withstand the hot exhaust
temperatures. It would be really cool to find a CO sensor that you could
stick in the exhaust and that would work with the Nighthawk.

-Mark McCulley