86 CGT miss - need advice

[David Head]

Son's CGT misses at idle (especially) - feels like it has better power
at higher speeds. Spark is good. Center cylinder, has reman head.
Swapped 2 injectors, little or no change. Swapped lines, miss moved with
lines. So it looks more of a fuel distrib problem. 'But' the seals on
all injectors are in pretty poor shape - its VERY easy to pop the
injectors out.
How much of an issue are injector seals?

Dave Head