Reply to "Air-Fuel Idlle Adjustment"

If you adjust on the Smog machine, you'll find that as you lean the mixture out, hydrocarbons go down, down...then they shoot up to the moon. At some point, you lean out enough to get a single-cylinder miss, which allows that cylinder's gasoline out the tailpipe where the smog sensor is waiting. FYI, your 30+-year old Motorcraft carb is in dire need of replacement, I suggest. Few-to-no shops work on those carbs anymore, and even finding rebuild kits is not easy. What year is your Pantera? In CA, '73 and older are exempt from testing, so many '74s which were actually built in 1973, have been re-registeed as the year of build, so this nonsense goes away for them. Others apply for "Historical Auto" plates which are also somg-free.