jamie956

When cold my rpm is up and down it drops to the point of cutting out then picks up again, dose this until it gets warm the idles fine.

Could this be idle control valve fault.

LEONMEX

Idle valve probably at fault,can be cleaned out with carb clean or soak in petrol. Check for air leaks aswell as this can also cause rough idle .

Cos500

Hunting, my old sapphire did it, cleaned out the idle control and it was fine after that

Knuckles84

I've just been through this same problem

Turned out to be a combo of cleaning out the iscv and replacing all the inlet manifold gaskets. They were all perished being on there since 1988.

Air leak on inlet creates surging when cold. Once warmed up it stopped surging but sat at 1200 rpm

jamie956

Pulled the iscv last night and it was clean washed it out any way with a bit of clutch cleaner,

When doing this i noticed that if i put some in the end it would leek out through the two slots in the sides, should this be air tight.

Its a brand new engine so gaskets should be fine saying that i have had the inlet cover off so may be it didn't seal back up when i re fitted it.