I'm having a problem with my 97 1.6 A3 (one of many problems i've had /ubbthreads/images/graemlins/cry.gif). When idling, the revs fluctuate. It generally idles at about 1k but sometimes drops to about 500rpm and occasionally races at around 1500 rpm - this is at its worst when lifting my foot entirely from the throttle or in the first portion of its downward travel when you can see the revs "drop off" or blip under normal idle leading to a stall though sometimes the ecu?? seems to catch it in time, preventing the stall. This sometimes has happened whilst moving when I have removed my foot from the throttle, which is obviously dangerous as you lose PAS but generally occurs at lights when accelerating and lifting clutch at same time. (I have to overrev before lifting clutch now to get over initial blip - which sounds terrible) Having looked at few similar posts to this I intend to check... Throttle body (clean) ECU (unplug or disconnect battery) Coolant temp sensor (no idea about this) The coolant temp sensor seems like a favourite as the problem started about the same time as I got a hole in my radiator and I tried using radweld (or similar) and I wonder if this has fouled the coolant temp sensor. If anyone has any other ideas or advice on doing any of the above I would be grateful.