At the end of a 300 mile trip loss oil pressure and the valves were noisy so I pulled over and shut it down. Checked oil which was just changed and okay. After letting it sit for a few moments started engine and it sounded fine, ran fine driving in city. Started on return trip and same problem again, had to tow car back home almost 300 miles and not a cheap thing to do. After sitting a day I started the car and it ran fine. I drove it local for 2 weeks with no problems and then it did it again. I have had 2 different mechanics looking for the problem but cannot find the problem, frustrating, too nice of a car to not being able to drive.