I have an '03 Sierra 5.3L that has just developed some idling issues. When I start the truck cold it idles fine but when I start driving and then come to a stop (traffic light, e.g.) it begins to idle very low and nearly dies. It did die once but has since only idled low. I initially thought it may be an electrical problem (battery, alternator) but they both check out. I have no idea what this could be. I would appreciate any help you could give me. Thanks!
