I have a 2004 chevy tahoe z71 5.3L with 133,000 miles. Once or twice a week it will not start up. Lights and radio on, starter cranks but engine will not start. Wait 15 minutes and it starts right up every time. Runs fine. I do have codes p0496 and p0442, replaced purge valve, vent canister and fuel cap but still have codes. Not sure if they are related to starting issue but it does seem to be fuel related.

 

Welcome to the forum. Check the fuel pressure when it won't start. That will indicate the fuel pump condition. It should be in the 50 to 60 psi range when the key is in the Run position and the engine isn't running.

 

I second the fuel pressure check, pressure should also stay pretty consistent once running and not bounce around.

 

Had issue starting again today, but noticed the anti theft icon flashing in dash as I was trying to start engine. When I came back to car the light was off and it started right up. Could this be passlock sensor? Seems like a common problem online. The passlock system will lock out for ten minutes which would be why it starts right up after I wait the usual 15 min.