Anytime I have an engine that is normally reliable and runs well and all of the sudden doesn't run properly in a different craft, 99% of the time the fuel system is to blame. That's why I suggested the test stand with a known good fuel tank/system to eliminate all variables to determine if it's the engine or the fuel system. I had to do this with a TT .46 where on one craft it ran like a Swiss watch and in another it wouldn't throttle or idle worth beans. WOT great, anything less and it would quit. On the test stand it ran like a Swiss watch again. Changed the fuel tank and all was well again.