Over the past two years, my 2003 Ford Explorer Sport Trac seems to get vapor lock in the summer. But it doesn't happen all the time. When it happens, I'll take it into the dealer, but the service team can't duplicate the problem. What happens (sometimes) is that I'll drive it to the store (maybe 6 miles), turn it off and shop for maybe 10 minutes. When I return to the vehicle and start it, it will sometimes not start, or, if it starts, it won't let me go over 20 mph. I had the fuel pump replaced in March (it's now June) and that seemed to help. But the other day, out of the blue, it happened again! We also had a new fuel filter installed last March as well. Why does this happen?
