out of gas vs sufficient

out of gas

prep
  • Tired; lacking energy or motivation. 

  • Used other than figuratively or idiomatically: see out of, gas.: lacking fuel. 

sufficient

adj
  • Possessing adequate talents or accomplishments; of competent power or ability; qualified; fit. 

  • Of a type or kind that suffices, that satisfies requirements or needs. 

det
  • A quantity (of something) that is as large as is needed. 

  • An adequate quantity of; enough. 

How often have the words out of gas and sufficient occurred in a corpus of books? (source: Google Ngram Viewer )