Idle problem.. Driving me crazy

[Jam127]

Soooo.. Done the swap with my old car (was in an accident ), single turbo gte 6speed into an na shell, all went pretty well with not many problems.. Anyhoo im having a bit trouble with steady idle.

When cold it seems to sit where it usually did with an odd blip here and there which i remember it always has. Almost like a small missfire that hasnt caused an issue before

When hot it will sit again normal like it used to with its odd blip

When given throttle it sometimes takes its time to come back down as if the throttle butterfly is sticking - which its not

When driving and i put my foot on the clutch from higher revs it drops and rises from around 600-1100 rpm for around 10-15 seconds then settles again.

One thing i noticed was different on the tt wiring loom and the na loom is there is a plug going to the bottom of the rad that went to some sort of sensor on the tt loom. Now i have read and read about idle problems and people mentioning that the fumes smell rich (which mines does) which is quite alot of the time down to the water temp sensor.. Is this what is at the bottom of the rad on tt's?

I have had the car smoke tested for vac leaks etc and all good.

Also cleaned icv

So this is the only thing i can think of, am i heading in the right direction or miles off? Also how would i go about wiring this part of the tt loom into the na one if need be?

Tried my best to explain :/

Thanks in advance

[Jam127]

Forgot to mention i have an apexi ecu with commander and that is reading the temp fine.. Just started it up from hot and its idling very low with heaters etc on

[Jam127]

Found it! Water temp sensor plug knackerd and wires arent great. Gove them a wiggle and idle goes crazy! Problem pin pointed