Lack of power - TD5 disco 2

Long post - sorry!!!

Looking for some advice please I currently have a D2 and I am having a nightmare with him! So about 4 months ago, I had driven about 1/4 a mile and all of a sudden he had a loss of power and we struggled to get up a little hill! He was then like that for the rest of the journey! So just thought he was having an off day as the next time we drove him he was fine! Fast forward to now and he is still doing it! So we have done the following -

Power steering component box has been replaced (not relevant to lack of power but just listing everything we have done)
Turbo actuator bypassed
Rocker cover gasket replaced (not relevant to lack of power but just listing everything we have done)
MAF Sensor
Air bleed valve replaced
Fuel return valve replaced
Fuel filter replaced
MAP sensor cleaned up
ECU had oil in and we have cleaned this several times
Injector loom replaced
O-rings have been changed about 1 year ago (genuine land rover parts)

And he is still struggling!

So for example, I drove him for about 5 mins today and he was fine, husband took him out about 10 mins later for about 5 mins and again was fine, then we have just taken him out now and was fine on the way to dog walk but on the way home, driving home then total lack of power and can only get up to 40mph!

He has been in 3 different garages and he always behaves when a mechanic is looking at him!!!

Does anyone have any ideas of what it could be or what we could try next!?

Thankyou so much!!!

Sticking turbo wastegate actuator rod and valve thingy on the turbo?
Does it ALWAYS go back to normal on start up?

Much info but very relevant parts are missing
1. Is it manual or auto?
2. Eu2 or Eu3?
3. the EGR is still on?

In the past I had also issue with power related to MAF. In my case it showed up right after start and gone in about 10 sec. after the car run well. I changed the MAF to genuine and problem was solved (it was an EU3 auto).
Have you tried to drive the car with the MAF disconnected?

Tamar Aldridge said:

Turbo actuator bypassed

Click to expand...

Not your problem but thought this wasn't recommended on the Discovery?

Three things (possibly 4) in my case, 1/ dodgy MAP, 2/ boost actuator diaphragm rod thingy came loose, lost its nuts, 3/ low oil in auto box. (4/ possibly, dodgy MAF.)

But obviously this is just one person's experience and others will have had different.

That's why the engine's type is important cos MAF can be blamed only if it's Eu3 or if it's Eu2 only if it has EGR fitted

Mine been running like a pig for months, but is strangely running great this week.... and Ive done nothing to it.

Ive had new genuine MAF, new injector loom, new genuine ATT, EGR delete, new radiator, new thermostat, new fuel filter, fuel return valve, air bleed valve, and fuel pressure test which shows a healthy 4 bar. Still plays up... only faults that have come up lately are driver demand faults.. which will now be looked at.

Have you had a diagnostic device connected to it to read any faults... trust SF in his comments, he knows his stuff on TD5's

OP still not come back with answers, I see!