1.4 MPI Cold Start problem

Just recently bought a 2000 Polo saloon with an 8-valve 1.4 MPI engine. When I start it from cold it seems to hunt for the correct idle speed, going from about 600 to 1200 rpm and back. It does this for 20/30 seconds. The if I'm driving at very low revs (lets say trying to get out of a tight parking spot) it does this hunting business again when I put a load on the engine. If I can just take off at reasonable pace it seems fine. Once the engine has warmed up it seems to go away. The temp gauge gives a reading of 90 when it's warm. I have bought a coolant temp sensor which I still need to fit (just in case).

In hindsight the issue was at low revs in general. Even when the engine was at 90 getting in or out of at tight parking spot was a bit of a nightmare. After changing the coolant temp sensor there was no change. Took off the engine cover to change the two air filters, found quite a bit of oily gunk in the throttle area. Cleaned it up using carb and throttle cleaner.....problem disappeared. When I drained the old oil it looked pretty goupey, may have been the source of the excessive gunk in the throttle causing it to stick at low revs.