Work on a muffler, say (4)
I believe the answer is:
knit
'work on a muffler say' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for knit that I've seen before include "become closer" , "Mend" , "Become joined" , "Use needles to make clothes" , "(Bone) heal; contract (brows)" .)