By the way, the embargo did not happen during the Carter Administration. It was from fall 1973 to spring 1974.
https://history.state.gov/milestones/1969-1976/oil-embargo
1973 is when Mexico began exporting oil to the US, a very small amount.
http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=pet&s=mcrimusmx2&f=a
When their total oil production rose with the new fields, that is when their exports to us became more significant.
Okay - have to get back with grandad since he was the one ranting about it.