So, I was half right!
I had the same problem when I installed my Polk components up front. I had soldered all of my connections, put the dash back together, worked great in my driveway. Took her for a test drive, and on turns, etc. the left tweeter would cut out. Was pissed to all hell, left it for the night, disassembled it all the next day to find that the soldered negative connection had broken, but because I had used such short leads, the wire was still in contact with the connector, so when I would turn, the wire would move, disconnect, and then would reconnect when I came out of the turn. Funny now, but I was pissed at the time.
Anyway, glad things worked out for you!
