What kind of engine do you have?
When does it cut out?
How is it set?
Does the engine lag when you go from Idle to Full Power? Does it cut out then?
Are you sure that this is an engine problem rather than a fuel problem?
What have you done to tune the engine?
Do you do a nose up test?

There are a ton of questions here. I was having similar problems that I figured out were not tuning issues, but rather fuel line issues (my line had a 90 degree turn in it that made fuel flow a problem). Please provide some more specific information.