Help, this has been going on for awhile now. Truck drives great, but every once in awhile especially when it's hot temps out, the security light will go on and then once I park the truck and come back to it, it won't start. I wait 10 min. every time this happens and then it will start again. I have replaced fuel pump, regulator, relay, battery, battery cables, electrical wires connected to pump, fuel filter etc. I have heard many different theory's although, none have panned out to be correct. One thought, was from a lock smith, who said that it could be related to the key or micro-chip in the key and it doesn't read it correctly, therefore won't start. If this is true, then what? Thank you for any advise you have to offer.

Depending on the year of your truck it is most likly the passkey system. My suburban did this a few times before it just no longer recognized the key at all and the truck would not start (you only have so many times before it locks out). In my case it was the ignition switch itself and they were able to replace that and key it to the rest of my truck. Just a though before you get stuck somewhere. :disappoin