Rev issues!!!

Hello. I recently swapped my car for a scooby sport special,
Im waiting on a new idle control valve coming from the Bay.
When i turn the car over mostly when its cold and no heater blowers or lights on it will cut out. When i turn the heater blowers on then turn car over it will rev fine.
But, when the car is warm and driving about, the revs will bounce off the needle almost stalling the engine. (which it has done few times)
I know the revs will go up slightly when you turn the lights or heaters on a/c etc.
Will this ICV that is coming cure this problem. Or do you think it could be something else like the coil pack?
Any help or advice will be great.

Well it wasnt the ICV as ive put new 1 on today and its done nowt!
Im beginning to think its something electrical as it only happens when lights and heater are on etc.
Any help would be great if anybody has had similar problems.
If i cant sort it out it will be getting sold lol

Could be quite a few things mate. Battery, alternator, fuel filter, cam or crank sensors, water temp sensor etc .

So diagnostics is the solution to pinpoint what it is?