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