vicomel

I have been getting cylinder 2 misfire codes the last 8-10 days I have been on the track. They have been intermittent and only at the track and not on the street. Sometimes they pop up and then disappear, and other times they stay on. The engine has always been hot when they occur and they occur after being on track for at least a lap or 2. They were never accompanied by loss of power or any evidence of a real problem. I would just erase the code, get back on the track and just run the car until I got another code and I would just erase it again. I was at the track this weekend and the same thing happened but I got codes that cylinder 2 and another cylinder were misfiring. The only change in the cylinder 2 misfiring code was that a P was after the code. Again, there was no loss of power, and I just reset the codes. Then during the 3rd session yesterday, I lost power like I was only running on 4 or 5 cylinders, came in and the OBD showed I had 3 misfiring cylinders, including the original cylinder 2. I loaded up the car and when I started it up, all was good and there was now no power loss. I drove home about 1.5 hours with no loss of power, the car ran fine and I even gunned the engine 6 or 7 times to see if any codes or issues would show up and all is fine. I did have all the spark plugs and coils replaced about 3 years ago so they have about 10,000 miles on them. I also had an oil change about 1000 miles ago and use the Porsche recommended Mobil 1 (0W-40 I think).
Any ideas?