2007 Won't Start After Removing Remote Starter

[Dale77]

My 2007 Sierra Classic 1500 w/ 4.8 engine will not try to start after removing aftermarket Remote Starter. All of the normal lights and sounds come on when I insert the key and try to start it. The radio, lights, etc. all look good. I am wondering if the factory security system (Passlock?) could be the problem? I was having performance and shifting problems before today and brought the truck to the dealer. They could not diagnosis the problem and said I need to remove the aftermarket remote starter before they can proceed further with their troubleshooting. I disconnected the battery and removed the device and terminated each wire with a connector. Any one have suggestions? Thanks in advance. Dale