Slight combustion on deceleration 5000 cs tq

[Ben Swann]

An annoying symptom has been present on the engine which was recently
rebuilt and was present prior to rebuild, but I attributed at the time to
exhaust manifold leakage.  I notice a slight rumbling on deceleration which
indicates there is fuel being supplied to injectors even when deceleration.

I'm trying not to jump to any conclusions, but is this likely the
deceleration shutoff valve being bad?

Any tips other than those in Bently(25.15) to check?

Is there something else I may be overlooking?

The engine has also been a little hard to start.  I beleive most of these
symptoms to have been present prior to all of my recent work, which was
supposed to take care of these things.  Of course none of the fuel
injection system was replaced, nor the O2 sensor.  I did find at least one
injector leaking down even though they are only a year old - there may be
others.

TIA

Ben