It was the CHT. It peaked at 500 (redline), after I went full rich within 15 secs of the alarm it stayed at about 415 (inthegreen) till another 20 secs I turned the A/C off. Then it went to mid 300s. It was the hottest of all the cylinders the rest of the flight. It didn't exactly make a happy sound after we parked it, it was making a sizzling sound so he's having it looked at to make sure everything is fine. I'm not sure that sound was normal, I'm hoping it's not a cracked cylinder head...