Off idle stumble when warmed up

[Cade Carvell]

Hi all,
  My 87 4kq, has developed an off idle stumble.  Here in Minn. it is
now 10-20 degrees on a good day.  Anyway, It has lately started giving
me an off idle stumble, ie at a stop sign, idleing normal and warmed up
fully, then i go to hit the gas and move, and well, it just kind of
falls over itself, then all of sudden (usually after 10 seconds), it
picks right up and off we go.  The odd thing is this doens't happen all
the time, and seems to be most prevalant when the car is fully warmed
up.  I did notice that when the engine is cold, not plugged in and left
outside, it idles fine, but accelerations is a bit choppy, not real
noticeable, but you can tell it is there.  I figure this is just because
the poor car is at 0 or 10 degrees, and im lucky it still likes me enouh
to start each morning.

  I checked under the hood for vacumm leaks, but when it is 10-15
degrees, this check doens't last long, before one loses feeling in there
hands.  But I am figuring that it is a vacuum leak, everything else
works great, plenty of power, etc.  Should this be something that I
should worry about and find a heated garage, or is it just an annoyance
that I can wait till spring to clean up.

Thanks for an insight,


Cade Carvell
National Business Systems, Inc.
2919 West Service Road
Eagan, MN 55121
Office: 651-994-4400