Felicia pickup rough running

Hey everyone, been a while since I had to use briskoda but my truck seems to dislike winter as have issue with my pickup engine that iv half sorted I think but as usual any help is appreciated, noticed lately on damp mornings the engine runs tad rough , well more so than the usual Felicia rattle lol and hesitates slightly for second when throttle applied but two days ago lost completely any top end power and slight judder from engine when pulling away? Now it's always been on list to replace the battered original HT leads so did it yesterday and it's back to normal.....kinda.    Idle is better but can hear slight hissing and if I accelerate in lower gears I can hear slightly different tone from under the bonnet. More throaty sort of sound , can only describe it as sounds similar to a car running with no air box? Just kind of worried about possible vacuum leaks as mines the 1.3 engine with a carburettor. I'm off out in it shortly so I'll post anything new an any one had experience with anything carb related I'd appreciate picking your brains lol cheers