You won't save fuel by pressing the clutch and coasting down hills
All modern cars with fuel injection (all diesels are fuel injected too) will cut the fuel supply completely on the over-run, so when using engine braking downhill you're not even using the small amount of fuel that an idling engine would consume.

Every little helps.
(WillI'mNot logs in twice a year, every year, Mon 10 Jan 2011, 11:50, Reply)