Am I in limp home mode?

Ok looks like the intercooler, I took it out today, filled it with white spirit and there was a tiny amount seeping out around the bottom right corner, that area was quite gunky so guess it might have been going for a while.
Would that cause my problem?
now what to do, replace with one from ebay or get a performance one, are they worth it if I'm not going to do anything else to it?
Already EGR taken off and there's some kind fuel map thingy fitted.

Se if you can make a cheap repair and test to see if it solved the problem before buying new parts.

Replaced the intercooler with nearly new one (No point in temporary repair) suspect hoses all
replaced, car runs much better than before but still same fault, as soon as I hit 70 I get a loss of power and speed drops back to 60 with some black smoke.
waste gate actuator moves, is there another way of checking its actually working?
Could it be the turbo ?
MAP clean
MAF same fault with it unplugged
Full service including fuel filter.
No Oil in red plug

any more ideas?????

Get some one with a nanocom to take readings whilst driving and when the issue happens take a look and see what's going on. You could carry out lots of expensive guessing

Has anyone got a nanacom in the north kent area that fancies coming for a ride with me?

Sounds v waste gate to me .....

Have you had the heat shield off and the actuator rod too? (watch that little circlip - it can fly some distance apparently....) Good soak of the waste gate shaft in 3in1 and bit by bit it went from barely able to shift with molegrips to finger light and solid click into 'closed' position. I think it was jammed slightly open, so losing some inlet pressure under normal running, then over-boosting under load - No probs since, and noticeably better power generally and defo better boost under full load. It might not be that simple - but mine was on the same symptoms. Never got round to ti, but now its working I ought to tinker with the adjustment for max boost without over-boosting. Good luck A

Disconnect the wastegate actuator arm completely. The wastegate arm should move very easily with just finger pressure and youy should feel it hit the stops either end of its travel. If not you need to lubricate with some plus gas or similar and work the arm back and forth until it all moves easily. Dont beat on it with a lump hammer just ease it slightly a bit at a time and it will loosen up.

Right, got it sorted now,
turned out to be the MAF sensor after all. I had unplugged it and driven it but the symptoms were still the same (I had read on here somewhere that if you unplug it then it resorts to default settings and you should feel a difference). Now I think about it, if it had failed completely then unplugging it wouldn't make a difference, so what actually happened made sense.
All in all I'm happy as it showed up a leaky intercooler and pipes that looked on their last legs. The car nows goes better than it ever has and the fuel gauge goes down a lot slower

Happy days.