This is a strange thing for me. I replaced two EGT probes (#2 and #4, burned out), didn't touch anything else. But the first flight after the replacement, the #1 CHT is showing about 60deg lower than the rest. The CHT curve is shown below. I had a few more flights after that, all showed similar trend. It started ok, when reducing power, the #1 CHT drops. EGT looks normal, engine is running fine. I will swap the CHT probe next time I get to the hangar to see if it's probe issue. But wonder if anyone has seen this and have a good explanation. I don't believe the cylinder is actually that cold, but can't explain the data. Thanks!