Hi, Haasman - when I originally had the problem, I thought it was temperature related, but I don't think so anymore. It can happen first thing in the morning, or when I'm ready to head home at 5 pm. It is more likely to happen when the engine has been off for a bit, though. It is behaving just the way it did when replacing the OVP stopped the symptoms. That was only a couple of months ago though.