ZD30 Unique Problem

So I have been looking around for months for this exact problem all through the internet, engine bay and where I could think, knowing the problem is still there is my biggest headache. My missus owns a 2004 model y61 Gu ZD30 and it won't get past 80 unless going down a hill, in neutral it will hit redline @ 4500rpm when in gear with clutch in it'll hit 3000rpm
I changed the intercooler due to it leaking, I then put the terminals back on the battery and on the first start up it hit 4500rpm in gear but then appeared to go back into limp mode at 3000rpm.
I tried checking the MAF and looks clean but am waiting for some CRC cleaner as I leave in a remote community in Cape York and no automotive shops around.
Also thinking about buying the ECUTalk OBll scanner to find out the fault.

Might need to reset the ECU, by disconnecting the battery for an hour. While you're waiting, check your work and also see if you have knocked any hoses or cables off.

You don’t need to buy the Ecutalk. You can simply bridge contacts in the plug and record the flashes.
There’s a thread here on this forum that explains the procedure if you want to do a search..

MAP sensor?

Want to clean the MAF but need to order up some cleaner and a set of torx keys

And is that with a zd30 pre crd

Theres a ton of these Patrols driving around. I would see if you can borrow a MAF out of another car to see if there is any changes. Its only going to put the donor out about an hour tops. If you are 100% the MAF is not the issue. Change the fuel filter, if no change. Make sure all the hose clamps before and after the fuel filter are on tight.

Is it blowing black exhaust smoke when you try to get it past 80 kmh? Check all of your vacuum hoses for splits or breaks and ensure they have not come off under the intercooler when you worked on it. They do become perished / brittle over time and can break easily.

Nah she only blows a bit of smoke when reving it and only gets to 3000rpm and under load. I'll check that today