Post it in the dealership section, thats what its there for. Bash the hell out of them for all we care.

 

The over reliance on the error codes for diagnoising may result in the wrong parts being replaced. Misfiring may be caused by even fouled sparkplugs or bad fuel injectors. A defective head gasket or valve stem seal could cause the sparkplug to foul. So, did anyone check each sparkplug for fouling? Was the fuel filter changed? A plugged fuel filter may make the engine loose power and misfire. Was the air filter changed? Did you look for vacuum leaks? Perhaps an improperly installed timing belt could cause the lack of power and vibration. How many miles were on the car in 2005, when you bought the car used. Did you get the repair history from the previous owner? Has the engine ever overheated? Many auto stores will scan your car for the OBDII error codes for free. You could also use any OBDII scanner or VAG-COM from www.ross-tech.com. You could also buy the BentleyPublishers.com Audi shop manual CD. However, you have already taken the car to several different experts and they seem to have failed. A mechanic may have to deal with an angry customer with a car with a multitude of problems, which are impossible to diagnose. So you were sold a cataylitic converter, but the cause of its failure was never fixed.

 

You've got that right. My kid was taking autotech in HS and except for basic thoery, ALL they taught was 'error code troubleshooting'. Kinda discouraged him when he knew the problems by symptom and not error codes but couldnt use the knowledge (damn standardized tests).