I will be what I will be

Hi Tim,
"I am that I am" was a mistranslation by a monk named Jerome in the 4th Century who was translating the Hebrew phrase Eyeh Asher Eyeh. I will be what I will be. Ehyeh is the first-person singular imperfect form of haya. It refers to an action that is not complete so it is future: I will be.
  
The Tetragrammaton's meaning is lost in the mist of the past. God wanted his name published and commanded it to be published but by the third century BC it had been expunged from the scriptures and replaced with four letters Yod-Heh-Vav-He. These may have been an abbreviation or even a red herring to mislead the enemies of Israel from finding God's name.

I prefer how David said it YAH. It occurs 23 times: 18 times in the Psalms, twice in Exodus, and three times in Isaiah.

It is interesting to note that his name has been expunged from the New Testament also. In both the old and the new it was replaced by the word lord.  This leads to confusion because the Greeks and the English have only one word for Lord whereas in Hebrew there are two adonai and adoni. 

Adonai was used exclusively for Yah and adoni meant a human master. So when David says the Lord said to my Lord, he uses adoni for the second lord meaning Yah said to my Master (the messiah)

Hope this helps
Peace
Robert