[micacrumb]

usually under the conditions you are described it could be a couple of things you need to check, the air filter for dirt or obstruction, In my 02 Beaver with a 300hp cat we had a swallows nest in the intake of the air filter. The other thing is to check both fuel filters one for water and the other for the dirt. I'd change both if it hasn't been done with the last oil change or the last 6 mo. Hope this helps.