I and my daughter are restoring an 84 Turismo 2.2 and have reached an irritating problem. We have the car up and running most of the time but it will simply quit while crusing down the road. Once it quits it won't start again and usually will not even turn over. The battery measures 12.21 volts at this point but we always put it on the trickle charger while going through everything that we can think of. The alternator has been taken out multiple times and tested at multiple shops and passed muster every times. The voltage regulator was good but we replaced it anyway. When running, the charging indicator reads at mid position, which is right where it should be. Each time we put it back together it will start right up, run for a few days and then quit again. We have been battling this for almost 6 months. I'm the patient type but this is getting to me. We are obviously not looking at the right part of the system. What kinds of tests should we be performing in order to nail this problem down?