idle trouble and genral rough running

[ross k 10]

hi guys after some help i did an abf conversion on my corrado around 3 months ago. Its still running kjet and it ran sweat as a nut up until a couple of weeks ago. The started sounding really rough when you started it but very rarely if you turned it of and back on it was fine anyway it now happens more regularly especially when cold the idle is also unsettled its fine sometimes but then sometimes drops to around 450 obviously making the car splutter if you rev the car it will go back to normal but may do it again later. I think its running rich and it pops a bit on over run which it didn't do before any ideas i have cleaned the wur and the contacts of the sensors on the side of the head thanks ross