2003 Silverado, 5.3 engine, had it about 6 months - Usually starts very quickly and runs great. Sometimes when I try to start it, it doesn't start right away and when I release the key, it continues to turn over till I manually turn the key "off." When I retry it, it cranks, but won't start. Have to turn it off and wait a minute or so -- sometimes it acts like it's flooded and sometimes it starts right up and runs normally afterwards. Is there a problem with the ignition switch on these trucks? Any ideas? I suspect that soon it will not start at all, and at the worst possible time and place.