Astra problems in the damp

I've had my 1993 Astra 1.6i Ceasaro for about 6 years now. It's on
122,000 miles but until recently it's never had a problem.

As it happens I was just taking it to the garage for an MOT and
service. It seemed to start ok but as I went to pull out of the end of
my road it seemed to lose power. After driving for a while it seemed
ok but I mentioned that it seemed a bit funny at the garage. As it was
having a service they claimed to have fitted new plugs although to be
honest I've not checked to see if they have - but they are a reputable
garage so I'd be surprised if they hadn't.

Well a couple of weeks on from the service and I assumed all was well.
Until we had a really damp cold morning. The car started first time
although it seemed a little bit sick but as soon as I tried to reverse
out of my drive it stalled. I restarted it again and found that
pulling away with anything under 2000 rpm would stall and below 3000
things were very sluggish almost like the handbrake was on slightly
(I'm absolutely sure it wasn't!). I guess it seemed a bit like my old
metro when the choke was left out only quite a bit worse. If I gave it
more gas than normal and upped the revs it seemed ok but I was having
to rev noticably more than normal.

Anyway - in both cases the car was fine once it had been running for 5
minutes or so and in both cases it was a very damp day. Yesterday and
today it has been running from a cold start with no problem at all.

I'm guessing some little component is not liking the damp cold - any
ideas what it might be?

Hope you can help,

Kev

 

idle control valve if fitted would be my first port of call.
then p'haps the coil, then the centre plug lead from the coil to the ign
system.

mike