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AFM fluctuation

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I have a different thread on here for a different issue but that has been resolved (thanks everybody) so started a new one for a much less severe issue.  I have an 81 zxt running MS3 and an innovate O2 sensor.  Car seems to run pretty good but was curious about some finer tuning so hooked up a digital AFM gage.  Driving down the highway at steady throttle/cruise, my readout is all over the place from 12 to 14, so much so that I really have to guess to determine the average.  The car is running smooth etc so all would seem fine but my gage is telling me my fuel mixture is all over the place.  


I am an old school mechanic, but am pretty green to this tuner world where computers are in control instead of a carburetor.  I cant imagine this much fluctuation is normal...is it?  If not, would be open to any clues as to where to look to get it settled down.




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Do you have the wideband hooked up to be able to log it with the Megasquirt? Take a look at both the AFR and the injectors pulse width at the same time. The two values should almost correspond with each other, as one moves, so should the other. If this the case, then you need to figure out what is causing the fluctuations, could be MAP or RPM reading inconsistencies. Also, post up your tune for everyone to see.

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