Recently when I drive for a while in traffic (stop and go) and then park my car for a quick errand and try to restart it won't start. This has only happened on extremely hot days ( over 90 degrees). I replaced the battery after the first time which was in April. It is now June and its happened 2 times in 2 weeks again. I have been able to start it after letting it sit for over an hour or with a jump. I'm getting nervous to run errands and the weather isn't getting any cooler. Any ideas of the cause?