Sluggish Between Shifts

[hairdryer33]

I have a s2 with the usual mods, how ever when cold or first start of the day I have to let it warm up like an old carby car as any throttle input, it runs really rough (sounds like it dropped a cylinder) for about ten seconds then picks up again. The fuel pump seems ok at wot given afrs are in the tens, but it does fluctuate between 12 to 16.4 when im having the cold start issue? It also runs rough sometimes between mainly second the third gear changes if im aggressive with the throttle, if I smoothly open the throttle it seems ok but if I just mash it she runs rough. Ive replaced the ecu (stock) afm, cas and tps. Any help would be appreciated

[GTSBoy]

Temp sensor, oxy sensor

[hairdryer33]

Could it be till the o2 sensor warms up? Its a pig to drive when cold but still doesn't explain the rough running once warm. Will replace the sensors and get back to you cheers

[Jordy32]

Have you replaced your fuel filter? could be clogging up

[hairdryer33]

Have done that yes