Impulse nytro not running well

[allanhanes]

I am working on a customers 2009 yamaha impulse nytro. 2871 standalone with non 02 correcting system. when hard into the throttle it feels like its running out of fuel falls on its face. it does not die and will idle fine. when he cycles the key its good to go untill he squeez's and falls on its face again and evertime. fuel pressure 40 lbs and goes up when building boost and back down when boost is off. changed rear pump as well. any ideas and help much appreciated.

 

[pylon]

sounds like a loose vacuum line or a loose wire on the standalone .

 

[zebiraross]

Have you changed the plugs? We've seen a rare fuel pump go bad and loose fuel pressure under boost. For sure change plugs and if that doesn't do it look at the fuel pump on the surge tank.