normally i'd expect cold weather sluggishness be due to gearbox/ird/diff oil viscosity
within the first 5 to 10 miles .. depending on speed / load ..
would also depend on engine oil viscosity .. untill running at normal engine temps
my engine certainly aint sluglike in the cold weather temps ..
the opposite .. cold dense air means more air-mass flow via the MAF ..
which translates into more go-juice available on demand
though .. don't think a leaking injector would be doing you any favours
( no idea how cold temps might effect that with regard to available power )
or how a standard egr system would effect power in cold temps
( my egr has been deleted .. so i've no idea .. could only theorise )
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another factor Might be fuel quality ..
although i think low temps need to be fairly extreme before diesel gets sludge-like
( can't remember what it's called ) ..
in north america .. used to be something called diesel2 ( i think ) for use in seriously low ambient temps
another factor could be any water-in-diesel freezing up ..
but that would show up as hard starting / crap running .. white smoke .. or non starting from a blocked frozen fuel filter ..
