Very Good ..
Actually, if there are no vac leaks and the fuel presure is OK, rich/lean limit codes do point to MAF. I just recommend those test before getting into the MAF , as they will cause the same faults and are first check tips.
But in order to tell MAF, it is best to get ECU adaptation readings with a scanner, and even then , they are so hard to diagnose for sure, that the Techs use the same approach/solution as you .. change it with a known good one and see if the adaptation numbers come back towards normal [ or , as in your case , take it for a ride]
Thanks for the note of appreciation . As far as SB is concerned , I am moving near there soon and I was hoping to get a job there sweeping the floors....

Take it for a good ride and the ECU will relearn and make the proper adjustments as you put some new miles on it..
See ya