I have a 99 A6 just dead one morning, my mechanic (not an audi mechanic) did load test and said alternator wasn't charging properly, so changed alternator, same deal, dead next morning, installed new battery, and seemed to fix it for one day, then new battery dead again, still don't know why it's dieing? Then it starts running rough, top speed 30-35mph, sporadic idle @1500 exactly until like you reach 2000 rpm, regardless car is not drivable. Ran standard shop obd2 scanner and said throttle body malfunction, so ordered a $175 used throttle body and it was wrong, mine is cable driven and replacement was vacuum/electronic driven, so it will be returned tomorrow. After all my reading for hours online, mine may not be bad? Never realized that a dead battery could trip all these codes and then need to relearn them!

So on a very tight budget, how do I get it running properly again, do I need to have a audi mechanic relearn throttle body?

Thanks in advance for any and all help!