Ethanol has been in most of our gasoline for years...
But your Intruder is about old enough, to make your question a very good one to ask...
EDIT: I just did some digging, and found that engines built after 2001 can take up to 15% ethanol...
Which leaves yours in a questionable position...
It would probably be best if you simply called a Ford Dealer, and asked them about it.