2002 A4 1.8t
Wont start on the first attempt ONLY if I drive for 5+ miles and then let the car sit for 6+ hours. (cranks but no fire off)
-If I go out and start the car (second attempt no problem) and let it idle for a second or even to warm up, when I come back after hours or even days it fires right up first attempt.
ALSO
-If I drive 5+ miles and let it sit for 4 or less hours it starts up on first attempt.

I've changed
-Mass Airflow Sensor
-Intake air temp sensor
-Engine Coolant temp sensor (green)
-Fuel Filter (factory OOOO)
-Air filter
-Spark plugs
-relay 219 under ECU (I guess its the ECU power relay??)

There are no codes and no check lights.

 

Sounds like coils to me

 

I got my coils all changed at the dealership not very long ago but I guess it could still be them since they suck. Thank you for the suggestion.

-Right now I'm waiting to see if cleaning the intake tubes and inter-cooler out makes any difference. (I found someone who said after awhile oil builds up in there from leaky seals in the turbo, then is sucked up in the intake. After shutting down for a while it pools in the combustion chamber causing an initial stating issue)

 

good point, just took my breather tubes off to get to my o2 sensor anf found alotta oil in mine.

 

I gave up! I sold my Audi for $4500. At least I don't have to work on it anymore
Very Bitter sweet I bought it a year ago running perfect, sunk a few thousand dollars on tires,sensors, and fixing up the interior to perfection all to get a sell it to a buyer who was still unsure because of an intermittent, infrequent staring problem. ---Done with Audi/VW!