I sometimes drive my dad's 98 A6 1.8 (The first generation to have the new italian designed styling) and sometimes when I start it up the engine revs itself, it goes to about 2000 rpm (maybe a little more) and then back down to idle then back up again and then down. I don't know if this is helpful but it doesn't matter what the temperature is outside it does it hot or cold. If anyone has any ideas on what it could be i'd be grateful. Cheers

 

Hi m8, took my A6 in for a service last week, i had the same trouble ,
changed my airfilter and plugs , now ok.

you might have the same problem. just an idea.

 

I am having the same problem with my A6 Quattro. I just dropped a K&N filter in it has gotten better,or should I say less frequent. I wanted to put a set of Denso Iridium plugs, but I got so much "Crap"[:@][:@][:@][:@][:@][:@][:@][:@] for buying a $50 Air Filter (K&N). I think I will post, and ask one of the "Smart Guys" for a suggestion....Thank you again.

 

fault codes

 

Check the codes and see if you've got a faulty coolant temp sensor. Mine was doing the same thing and got to where it wouldn't start if warm. I replaced the temp sensor (easy, easy DIY) and it seems that all is fine now. Just something to check out.