First things first Happy New Year to all

Ok so ive been fitting a recon head and some other bits over the last month and i came across one or two problems which most were thankfully solved by you guys (big thanks)
Now she is all back together and running again i still have an issue. When the engine has warmed up it runs like a dream im really happy with it but when its started from cold it appears to run on 2 cylinders for a little while then 3 then 4 when it gets warm.
To be honest ive not had time to look over the problem coz i always seem to be at work

It had a new dizzy cap, rotor arm, leads, plugs about a month before the new head went on and i reused all these parts.
Does anyone know what would cause this or has anyone had the same problems?
I apologise if this question has been asked before im pretty new here.
Another thing i should mention is that i got a hottuning stainless manifold whilst i had the head off. It looked great and the welding looked really neat but it did not fit. It was the correct one for my engine had just been made completely out of line with the studs on the head (very dissapointed but they did refund me ok)
So i ordered a mild steel one from ashley it fitted to the head like a dream but had no fitting kit with it and was about 15" too short to match up with standard exhaust so i got an ashley full system to match which was still too short so had to have some pipe made up to get it to fit, the welding looked a bit rough aswell. Now its on im really pleased with it it sounds good and appears to have upped the power a bit.
Car is 86 gti 8v kjet
Thanks in advance
