in gear vs on fire

in gear

prep
  • In a state of readiness or activity. 

on fire

prep
  • Excited, enthusiastic or passionate. 

  • Overwhelmed with emotion; beside oneself. 

  • Being burned by fire. 

  • Doing very well; achieving good results at a rapid rate. 

  • Sexually aroused. 

How often have the words in gear and on fire occurred in a corpus of books? (source: Google Ngram Viewer )