Related Clues:
- Sounds of well-tuned engines
- Motor noises
- Sings wordlessly
- Sounds from contented kitties
- Sounds from Abyssinians
- Runs perfectly
- Runs like a tuned engine
- Sounds like a well-tuned engine
- Buzzing sounds
- Doesn't remember the words, say
- Forgets the lyrics, maybe
- Sounds from happy cats
- Sounds from contented cats
- Sounds from a happy cat
- Carries a tune, in a way