Replaced Water Pump,
Join Date: Aug 2009
Location: New Zealand
A lot of modern engine management systems actually kill the injectors on the over run, to save fuel, increase engine braking and reduce emmissions - so popping and banging is eliminated. Noises which can also be caused by a leaky exhaust.
Oil consumption on the over-run can be caused either by a fault PCV system, leaking rings or valve stem oils seals. On the over-run a strong vacuum is created within the cylinders which will suck oil into the cylinder usually past the valve stem seals. If the engine is the type that doest cut fuel to the injectors, then you get blue exhaust smoke on a trailing throttle. Or a puff as soon as you push the gas pedal after the over-run in one that does cut fuel.
If the car is coasting/floating rather than engine braking, it could be serveral thing already mentioned before, it could also be an issue with the throttle stepper motor not allowing to the throttle to fully close. These things can't really be diagnosed remotely.
Darryl in New Zealand