hello

Problem that happened to me yesterday in the Competition,The first exercise is a loop with a snap at the top.
While the Snap the engine at maximum rpm , after the snap i Closed the throttle and when I open the throttle again the engine dead.
I landed, I checked the engine on the ground idle and maximum RPM and there was no problem,The second time I've flown I've had the same problem and at the same time.
At home, I checked all the fuel pipes, including the pipe in the fuel tank and I saw no problem ( in the tank has the special ys fuel clunk ) .
I fly this model airplane with this engine for two years and had no problem until now
the engine is dz160, the fuel cool power 30% heli.
Do you have any suggestions for me to solve the problem ?
Thanks

kobi