No...not my plane. But another T-51 owner has the newly installed LS3 engine. With a Link G4+ Xtreme ECU. The engine runs perfect, for about 15 minutes of flight. Then after getting warmed up, it misfires. No one seems to have a clue why. My money is on: 1. Coil pack that fails when hot, so plug doesn't fire 2. HT lead that has a break and resistance increases when hot, so plug doesn't fire 3. Faulty injector Anyone here care to take a stab at a diagnosis?