Power loss/ surging on hills 1kz te

[Thelocalsparky]

Hi, I've got a 05 kzn165 hilux that is loosing power. I think it's all through the rev range but is most noticeable under load over 2500 rpm. It is dropping 10 or twenty clicks on hills I used to cruise over? It feels like a misfire. I changed air and fuel filters, had injectors rebuilt, injector pump tested. Cleaned manifold, ran clear fuel lines all the way back to tank ( there is air coming in at the filter but no change in performance when I ran it from the tank to the ip). Removed pickup from tank, it was clean.I put a boost gauge on and it's reading 12 lb, I removed the muffler and air filter, cleaned egr.
The lack of power is doing my head in and I haven't tried towing yet, I've dreamt I fixed it a few times but can't remember how!

Any ideas would be much appreciated
Thanks in advance ..Jason