My BMW 325 will rev up to 2,000 revs (on a cool day, 1,500 revs on a warmer day) when it is started and drop down to normal tickover straight away.
My thoughts are a temperature sensor telling the ECU that it is a colder day than it really is so give it more petrol and then the ECU realises that is over reving and drops it down. Temperature gauge reads normal (exactly the same as my old 318) so I'm guessing some other sensor somewhere.
Any ideas? Like to get it sorted because I look like one of those people who scream their engines on start-up.
Regards