Freelander 1 TD4 Top-end vibration

Ok I know It's a bit vague but just chucking this out there in case I get a few suggestions I can explore.
At around 3500 rpm - less if going up-hill, more sometimes - I get a kind of vibration like the car is going over ridges in the road a few feet apart.
If I come off the gas they stop and becomes completely smooth, back on and it restarts.
Only really seems to happen if the engine is struggling slightly for power.
Anything spring to mid?

Fuel starvation?

Low pressure pump? If you have a diag kit, numbers have been posted on here as to what to expect.

Fuel pressure check needed. Hp and Lp. Report back.

Cool I'll plug in the Hawkeye and take it for a run.
I have a new lp pump already if I need to replace it.

maybe check vacuum hoses as well ..
as someone else had a similar issue .. and my hawkeye showed no issues ..
( like .. watching boost pressure when going uphill .. it looked normal )
turned out to be a small leak in a vac hose

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