Man you are between a rock and a hard place.
You have 3 ways to go.
On the code. 1351
http://members.troublecodes.net/crunch/1351.pdf
On the anti theft light you need to get it on a body capable scanner and retrieve body codes to find the problem on it.
Also always check fuel pressure on a hard start or no start.
You did not say what engine but if a muti port injection eng.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
Let us know how it goes and if you get any body codes on the anti theft system post back code no.
Good Luck MT
