2005 A6 4.2 SLine that has me stumped. I get a rough idle after driving for a while. Short drives are okay and drives at night or during cooler temps seem better. But I have been having idle issues when its hotter out after longer highway drives over 80 miles, when i come to astop i get the rough idle. After searching forums and trouble shooting and talking to the dealers things seem better but not gone... Here is what I have done so far...
Replaced 8x Ignition Coils
Replaced 8x OEM Bosch Spark Plugs
Replaced MAS and air filter
Replaced Coolent Temp Sensor
Replaced 1x Dynamic Motor mount
after all this things seemed fine but first hot day long drive i got the rough idle. if I shut the car off it may reset temporarily but seems to come back depending on how much heat sync has happened is all i can figure.... The check engine will fluctuate and sometimes stay on for multiple days then seems to clear itself? any help would be appreciated!