A common problem but not sure what will be causing it.
I have just replaced the fuel lines as they were rotten. Whist I was in there I took out the throttle body, fuel rail, plenum and inlet. A good clean up and paint. Also removed the TPS from the throttle body whilst cleaning, not sure if this would cause an issue as the TPS is keyed inside to fit onto the shaft of the butterfly valve so it will only go back on as it came off. (not sure how to set TPS up)Gave the ISCV a good clean with carb cleaner.
All back together and the car started up no problem at all but it is idling at around 1200 rpm.
I haven't ran the car properly for quite a while so I cant remember what is might have been previously!

So, I have disconnected the ISCV when warmed up which made no difference. Car starts and runs at around 1200 and when warm idles at 1500. Removed the hose on throttle body to make sure the butterfly valve seats properly and its ok.
The car does not hunt at all but does pop and fart a bit from the exhaust. Idle screw on the throttle body has never been touched.
car is totally standard.

Any offers on a diagnosis please.

Ta.