I have a 2008 gmc sierra 1500 4x4 .. Stopped a few weeks back for gas and it didn't want to start after fueling up. It would turn over and keep turning. So I shut the key off tried again, same thing. Finally it started. No problems with it starting until I stop for gas again..Same thing. so we replaced ignition and starter. Still the same issue. It has only not wanted to start twice while not right after a fuel up. Any ideas what it could be? Mechanic wants to change ignition switch and says after fueling up and it not wanting to start is just a coincidence. I'm beginning to disagree.