Is there another way to check the duty cycle for air /fuel adjustment other than using the #3 port on the diagnostic connector? I've found a lot threads on how to adjust using a multi meter, but all refer to the diagnostic connector 3#port. My car doesn't have a #3 port or an o2 sensor or, lambda control. Also, it has no cats or charcoal canister. I've corrected the vacuum leaks and now I'm trying to find the accurate a/f adjustment. Any suggestions would be greatly appreciated. Thanks in advance !