Hi

If you had a white smoke trail after flame out, it is a fuel feed problem. there is an air intake somewhere in the fuel line system. Some possible causes:

1 - tygon as harden over time and clunk does not move with plane
2 - UAT or other connections in the fuel line are allowing air to enter in the system
3 - Suction side of the pump is sucking air. Check the lines and eliminate all festos and connections in the suction side

Was your UAT empty after flame out?

Regards

nuno