Richard, Thank you for responding. The first test was; CO2-14.5 O2-.4 at 15mph. CO2-14.7 O2-.20 at 25mph. The second test (after the cat. installation) are as follows; CO2-14.5 O2-.3 at 15mph. CO2-14.8 O2-.10 at 25mph. I have been looking at the low vacuum rea... Login to read more.