I was wondering what the normal idle speed should be for a 2000 a6 2.7t 6spd when its warmed up. Sometimes it will idle at a little under 1000 sometimes it will be like 600 others like 800 and on occasion it will sit and bounce back and forth from like 600-800 like a rough idle. Anyone know what the cause could be? also it misfires on occasstion too when under a load. im wondering if the problem is linked

 

noone knows?

 

Idle should be around 900

New spark plugs might help a bit... otherwise test for vac leaks.

 

Mine is steady at 800-850 per the tach. And I have 119k on the car. Plugs or air filter is the cheapest first fix. Vacuum leak makes sense, too, but tougher to find.

 

can a vac leak cause mis fire on occassion too? and also whats the best way to test for vac leaks.. its not the air filter i have a pretty new one.