2007 Silverado turns over but wont start???
 

Hi guys! I am new to the forum. Ive been working on an 07 Silverado for a couple days now. It has a 4.3L, auto trans, 127k miles. I drove it to work a few days ago and the next morning when i went to leave it wouldn't start. It will turn over but not start. It seems to be getting both fuel and fire. I checked the spark with an in-line spark tester and it looked ok. I put a fuel pressure gauge on the fuel rail on top of the intake and it shows 55-60 psi. I'm wondering about the theft deterrent system but don't know much about that. If anyone has any ideas or if anyone knows how to permanantly disable the silly security system please let me know. I'm running out of ideas fast so you gentlemen are my last hope before I break down and take it to the dealer....