Hi all. As mentioned I have a 06 Denali. I'm having a bugger of a time. Car cranks excellent but won't start. Here's the story. Been having intermittent starting problems,thought it was fuel pump as it was original with 137000 miles. Replaced ,car started fine and ran excellent but ultimately died. Left it for 24 hours and went to trailer it home,get to truck,starts fine and put on trailer as I didn't trust it to drive across town. Was throwing code po443,replaced surge valve which after said and done was faulty,could blow thru it unhooked. It then threw code p1682 which I understand to mean ignition switch in most instances. Vehicle started fine next morning so I pulled it into the shop,shut off,and tried to restart,wouldn't start. Replaced ignition switch,still wouldn't start. Put in old switch it fired right up so got another switch and installed. Fired right up,left it running for 20 minutes or so,it died all on its own and wouldn't refire.It threw some new codes mainly to do with throttle body actuator but also the same code p1682. Any one have any insight? To recap-when cold and first start it fires right up,when warm it won't.