Yamaha F150 -04 poor performance

[HydroliftErik]

Having trouble with a 2004 F150.
when accelerating from standing still, it revs up to 4800-4900rpm.
but seconds later it drops down to 3300-3500rpm and the engine starts to shake and vibrate.
When the engine is in neutral gear, it revs to 6000+rpm easily.

i have checked the following:

YDIS, no faults.
Fuelpressure OK.
All fuel filters are new.
Vapor separator OK.
Electric fuelpump OK.
Fuelpumps OK.
Spark OK.
Injectors are cleaned.

it seems to me that the engine isnīt getting the fuel it needs.

Very thankfull for every tip,

Erik

[99yam40]

was any of this checked while problem was happening?

[HydroliftErik]

i have been testing with YDIS while driving, yes.
havenīt checked fuel pressure while driving.

[99yam40]

need to be checking if fuel pressure is holding in spec while problem is there

[rodbolt17]

why would anyone run a test on a motor in the range where it runs well?

YOU MUST test at the RPM and Load the failure occurs.

[Nautical]

Everything checked?? but how about the fuel ?? I would run on a portable tank with fresh fuel, but I think you may have re contaminated your fuel delivery system and have a restriction somewhere ie injectors.