*Please Help* TD5 low rev power issue

HELP pls pls
My V reg Defender Td5 has lost its low revs power. It went in bits and was only occasional when the weather was really hot ( like last summer ), then it would be now and then, and now it's permanent. Really sluggish in second, third and fourth until the revs build then it takes off. However, when I'm on the motorway it has power in spades between 50 and 70mph.
I've changed the MAF, looked for oil in the injector wires under the rocker cover, changed the turbo pipes, and replaced the turbo, looked for leaks on the fuel pressure regulator ( none ) and the symptoms have remained the same throughout.
Any help on where to look next would be happily received

Fuel pump ?.
I had intermittent power loss on my TD5 when it was still under warranty, every time I took it in to the dealer it was working ok and never showed any fault, then the fuel fuel gauge stopped working, I booked it in for the fuel gauge and they told me the sender unit on the pump fell to bits when they pulled it out so they fitted a new pump, I never had any problems with power loss after the new pump was fitted.
I friend with the same year defender TD5 had the same power loss problem and new pump sorted it. Not a cheap fix though.

I'm guessing that it's possible to test the fuel pressure although I'm not sure why it would perform so well at higher revs as the pump is electric right ?

Yes it is an electric pump and as I recall mine ran ok at faster speeds when it decided to play up. At lower speeds it felt like it was not running on all cylinders.

Sounds similar. It seems fine on cold mornings like this morning and only gets sluggy once it's warmed up... Is there a cold start/choke type mechanism ?

Have you changed the fuel filter.

Scooby22 said:

Have you changed the fuel filter.

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Uhuh... Serviced just a few weeks ago. It's odd. Feels like fuel starvation but boosts like a demon when the revs pick up. Reckon I should try a fuel pressure regulator rebuild ?

The problem is the intermittent nature, you have to be able to test things when the fault is there, that was my problem, every time I took it in to the garage for them to check it, it drove perfectly and the fault never showed up, the next day or so it returned then went again, I was glad when the fuel gauge packed up and they changed the pump.
I was sure mine was the pump as my mate had the same problem and new pump solved it but his did play up while the fuel pressure was tested.
I am not saying change your pump as changing parts without diagnosing the problem can get very expensive and not be effective, just saying it could be a cause of your problem. And you have to drop the fuel tank out to change it, not an easy job. Unless you cut a big hole in the floor.

Yeah, I've seen posts re nibbling out a hole to access the pump. I've ordered a pressure regulator refurb kit and I'll see if I can find someone to test the fuel pressure after the filter if that shows no joy. The fault is pretty much constant once it's warm now so I should get a show on a test. Total pita but at least as it's a Landy it still gets me around lol.

Well, not the fuel pressure regulator then

Got a code: 57 fuel pump drive load open. Does this mean I need a new pump ???

On the plus side I now know a lot more about my engine lol

So, today I changed the fuel temp sensor and blanked the EGR, with no change to the hot running problem.
Cold it runs like it's brand new but as soon as the needle reaches the right hand edge of the blue strip on the temp gauge throttle response dies until the engine runs above about 1800 rpm then he boosts like a beast.
I don't understand and I'm struggling to find someone who does

Best advice I can give you is to stop fitting new parts and changing things until you diagnose the problem, unless you have spare parts sat around you end up throwing money at it without fixing the real problem.

Scooby22 said:

Best advice I can give you is to stop fitting new parts and changing things until you diagnose the problem, unless you have spare parts sat around you end up throwing money at it without fixing the real problem.

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I've not spent a great deal tbh... Less than £200 and most of that was borderline necessary, and the turbo I can get back most of what I spent if I don't want to keep it as a spare.
The difficulty seems to be diagnosing the problem, or finding someone who recognises the symptoms. Plugged it into a code reader but no one answers when I ask what code 57 blah blah blah actually means

What maf did you put on?

Discodevon said:

What maf did you put on?

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Interesting question... I bought it from ebay as advertised:
FOR LAND ROVER DEFENDER 2.5 TD5 DISCOVERY MK2 2.5 TD5 4x4 1999-2004 MAF SENSOR

I read that if the MAF is faulty the engine will run better with the MAF unplugged as the ECU sets it to a default running mode, if the symptoms are still there you can discount the MAF as your problem.
If the problem goes it points to the MAF.

https://www.landyzone.co.uk/land-rover/td5-fuel-pump-drive-open-load-fault.312000/

Have s look in this thread

have you checked wastegate adjustment? It could be that it’s not closing off, in fact is it operating freely? Could you monitor boost pressure?

Pos110 said:

have you checked wastegate adjustment? It could be that it’s not closing off, in fact is it operating freely? Could you monitor boost pressure?

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Hey pos110, wastegate checked and replacement turbo fitted. No change