Working on gf daughters 2002 Audi A6 3.0. Codes are P0445, 2401,0418, 0414, 057, 037, 0141, 0161, 0102, 0031, and 051. I cleared the codes with scanner and the same one's come back. I replaced a couple vacuum hoses and T connectors. When you start the vehicle, the idle surges and sometimes drops so low it cuts off. When you put it in drive or reverse, its not drivable. I accidently broke the black plastic tube at back of engine that goes from the back of the right and left valve covers. Broke it in the middle. Now it doesn't surge and drives perfectly! Very strange? I taped the black plastic tube back together and it started surging again so took tape back off so she can drive it for now. Anyone have a clue? Any help would be grateful. Thanks