Hello, my #6 cyl exhibits the following problem: It has gone cold on two recent flights during descent. Engine is running rough when it is going cold. See two attached engine monitor plots. What has been done and excluded by the mechanic are the following items:  Check if valve is stuck. Negative.  Clogged fuel injector. It's a GAMI. Was filthy but not clogged. Was cleaned.  Check plug. Bottom was dirty, but could be due to rich run ups. Should not lead to cylinder going dead.  Air blow spider and fuel lines.  Swap injector. Negative.  Swap temperature probe. Negative.  Check valve guide and spring. Somewhat worn, but should not lead to cyl going cold.  Compression 65/80. But may change after 45 min flight. Should not lead to cyl going cold. Cyl #6 has 2100 hours on it, and has worked great every single time for the last 500 hours. Never any work performed. Plane regularly flown. Can't be magneto or ignition harness, since only one single cylinder affected. After all these  points, still during run up at 1500 RPM cylinder still goes cold, but after engine warms up it stabilizes and is good to go according to engine monitor. What else to check? Safe to ferry flight? (Plane is not at my home airport with limited repair facilities) Thank you!