2005 f115lrd

got used boat and motor about 46 hours on both has ben sitting with old gas replaced gas,filters engine will start and idol but when you give it gas it has a bad flat spot in throttle but doesnot die out also has new plugs any ideas does this motor have an 02 sencer if so where at?

[boats.net]

Need to have fuel pressure tested, may need to clean vapor separator tank, elect fuel pump and screen.