I own a 1997 Audi A4 1.8T. It has 111,000 miles, however had a new Audi installed engine installed at 86,000 miles. Over the past four weeks, sometimes when entering the car to start it, the car has no power, (clock stopped and no dash or interior lights). After waiting for 15 to 30 seconds, the cars power turns (dash lights and interior lights turn on) enabling me to start the car. Car runs great. The battery in the car is about a year old and the voltage meter is running a 15 amps. Any advice?