Disco 300tdi sluggish power

Afternoon all, ive a bit of a problem with my old 96 300tdi, tried numerous things along the way but i still haven't quite got to the bottom of the sluggish power it's putting out. (Gotten worse over the last 2/3yrs)
I started with the easiest cheapest stuff 1st of all, so far I've done the rocker/valve gaps, new fuel filter, timed the pump via DTI guage, checked the lift pump is pumping, replaced the intercooler for a double core (it was leaking a bit of oil from a hairline crack) and had the injectors ultrasonicly cleaned with new seals, im also getting 1.7bar of boost from the turbo.
I've just done a compression test but couldn't do cylinder 1 due to a seized glow plug, the following is what I got.....(on a cold engine)
Cylinder 2, 315
Cylinder 3, 300
Cylinder 4, 310
While they are all fairly even does a near 50psi drop on cyl 3 from the quoted factory numbers seem low? And what's the chances it's cylinder 1 giving me issues, I.e are they prone for blowing through that cylinder?
Any other pointers would be appreciated as I'm running out of things to try next other than pulling the head to take a look?

Cheers Pete

Try adjusting the delivery pump,

1.7 bar from the turbo is huge-in theory a diesel can never have enough air but that's the most I have heard about

If you turn the screw-at the back of the injector pump- from the 12 o clock position to the 20 min past position you should fly like a scolded cat

D1Nut said:

1.7 bar from the turbo is huge-in theory a diesel can never have enough air but that's the most I have heard about

If you turn the screw-at the back of the injector pump- from the 12 o clock position to the 20 min past position you should fly like a scolded cat

Click to expand...

Cheers I'll have to give it a look, the pump has already been tweaked before I owned it some 13yrs back, could it be the boost pin that's potentially worn?
It really is a head scratcher as although the compression results are lower than a factory figure they only equate to like at most 13% down, which brings me to my next question, whats the maximum acceptable drop in compression before it becomes a concern?

if you have been running 1.7 bar for 13 years and no issues that's brilliant

check the pipe from the turbo to the injector pump for a leak

it needs that pressure to push the boost pin down

D1Nut said:

if you have been running 1.7 bar for 13 years and no issues that's brilliant

check the pipe from the turbo to the injector pump for a leak

it needs that pressure to push the boost pin down

Click to expand...

Ah yes forgot all about that, it was 1 of the 1st things I'd checked all good and clear,
As for the boost, im assuming that my guage is accurate (a newer type electruc stepper guage actually shows higher!)

Also something else to mention my egts seem to be higher than that of my mates 300 in his series, granted the disco will weigh more but I'm taking nearly 200deg difference on the same stretch of road/hills, is this something that's associated with my issues?

Something to maybe mention, I'm running 33s but have been for the last 8yrs or so and never had a lack of power until recently

Also cheers for the replies, it's much appreciated