df 250 can't full throttle

[candrayudha]

i have problem again with my df250...the engine run normally when start n' neutral gear/throttle, but when i try to add rpm to 3000 the rpm going up and down...down...down...(not increase) till 700 rpm. in these case the engine will be shaking like the poor fuel in ignition....(note : the fuel system have serviced in low system and high) any one have solution for my case...pls. thanks.

[boats.net]

Check for fault codes, run fuel pressure test.

[candrayudha]

there's no fault code sounds out,....may be i should check the fuel pressure first for sure....thanks for info....

[artdf175]

Have you checked your fuel tank vent?
Almost sounds like it is plugged and you are creating a vacuum on the tank
One way to check is run until you experience problem then open the fuel tank fill plug