1.8 gti running problems

Hi i have a 1990 mk1 golf gti cabrio (kjet injection system) this is my second year of owning it and not had a problem so far (lucky me), now i think its all coming at once.  I am having problems getting the car to start on cold days  and even bigger problems when it has been raining hard.  It has been fitted with either a piperX or K&N induction kit rather than a panel filter so the whole bottom has been removed from the induction system and this stuck in place not sure if these can cause a problem.  When i finally manage to get it started which can take up to 5 mins it struggles to idle and keeps stalling on me when driving it down the road and misfires continuously when put under any sort of strain.  If you rev it while out of gear and let the revs fall it will stall again.  Oh and it also smells like its running rich.  I could do with some help with this as i have no idea what to try.  So any advice is good advice, please help.  Cheers.

Shane

probably is running rich. co and timing are a good starting point. cabriaulet has a co tuning trick. if you press the brake pedal and the revs drop, it's rich. in theory this should work the other way round too. turn the co down a bit at a time until nothing happens when you press the brake pedal. 3mm long reach allen key is required for this. do you know where the fuel mixture is adjusted? it's located in a small tube between the 4 fuel lines on the metering head and the big round rubber boot that has the plastic s tube going to the throttle.
 sorry if i'm teaching you to suck eggs, but it's the easiest way i can explain if you're not sure.

check the dm for dizzy cap and rotor arm for wear and corossion,

thanks for everyones help turned out that i need a new dizzy and arm like you said pain in the bum and the pad in the bottom of the cap needed oiling it was bone dry not something i would know about though so thanks again my car is starting again now lol cheers

happy to help