This is a very common problem on GM vehicles. The security system is notoriously known to
fail. Basically when you insert your key, the system checks for a certain signal. If the system
cannot get the correct signal from the key, it assumes the key is incorrect or you are
attempting to hotwire it. The system then goes into SECURITY lockout mode. (prevents
vehicle theft) This will either turn off the starter, or the fuel injectors. This has been happening
with GM's for a very long time. There are ways to bypass this now. Read through this page for
info, solutions as well. Google these for info diy-gm-security & newrockies