I am having the same problems with my Cheetah SE. It only flames out below 1/4 throttle in the air, will run all day on the ground. I get acceleration, fuel error and low rpm codes, no smoke at flame out. It has been in for repair a couple of times. I have tried different UAT's, high flow system and fittings. I put engine and power pack in a friends airplane and flew it, same problem. It has not been solved yet.
Scott