I have a 1984 Nissan Stanza with 140,000 miles.  I replaced the
eight plugs and distributor about 5,000 miles ago. I drive it only
about 1,000 miles a year.  It stays in a carport.

It almost always runs smoothly.  Occasionally after sitting a few
days, it has run rough for a block or so.  Today I ran it a mile
and it seemed to be missing on one cylinder all the way.  It was 45
F.  I last ran it a week ago.

Does that sound like water in an injector?  Should I add something
to the gas?