Wondering if anyone else has an idea on this since it's been awhile. Today my 03 z71 did the same thing. Connected the battery, a few clicks from the fuse block then the truck started. Keys were on the ground next to where I was working. I disconnected the battery, waited a minute then reconnected. Same results, clicking and starting. It would only run for 3 seconds then shut off. Finally connected battery, started with the key and drove it. Everything seemed to be working fine. I swear this thing is Possessed! Christine 2.0.