Hello and thanks in advance for your suggestions. I recently had a used motor put into my Audi A4; new hoses, spark plugs, filters, timing belt, on and on. The car ran great for about 2 weeks then the aternator appeared to be bad as the new battery was now dead. When I pulled the alternator out and found that the nut holding on the battery cable was missing. I had the alternator tested and it was good; put new hardware on it and reinstalled. Jump started the car and the battery charged right up and the car will start on it's own. The problem now is that it will not idle or run smoothly. There are codes; will check them over the weekend - any other suggestions?