Loss of revs/power 2.2 ctdi

Sounds like piston blow by, as the gap increases and diesels have such high compression. When the turbo kicks in, the pressure is restored.

https://www.google.com/search?q=Toyota+Corolla+2+Litre+diesel.+Why+loss+of+power+at+low+revs+when+warm

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Have the car scanned for fault codes. A power loss in a turbo motor can be caused by simple vacuum leaks. You can check for loose piping and clamps. There are various components in that car that could cause such a problem. These include the turbocharger itself, the turbo boost (N75) valve, wastegate and its linkage, the car's ECU, maybe even a non turbo fault like a clogged catalytic converter or vehicle misfire.

sounds like one of the turbo lines has come off that would explane both the loss of power and sound

"I have the same problem. Some people say hat the turbine is done. But the problem is that the turbine works normal, no excess smoking, no power loss. So that is why I went dipper into the problem. It turns out it could be the intake header gasket.
I will take it to a local mechanic and let him take a look at it.

naa i would look for vacuum leak check all small hoses and connections..

Sounds like your Mass Air Flow sensor is in need of service/ cleaning.

Sometimes losing power because there is not a correct air/gas mixture. Your car need a close to 14.6:1 ration to be perfect.
This ratio is maitaining by ECU, only if the ECU gets the correct signal from your O2 sensor. The O2 sensor is about 100 bucks. First to take off battery ground cable off your car for 1hour to clear out some error state. When putting back, if the check engine goes off for a while then coming back, replace the O2 sensor. Good luck.

I don't wish to worry you but I think the turbo kicks in at around 2500rpm and it sounds like it isn't doing so, hence the management light coming on. It could be that failing. Be careful here, apparently the turbo uses the engine oil to maintain its operating temperature and if the turbo seals fail in anyway it eats the engine oil, with the resulting total failure of the power unit. So if you do nothing else, keep an eye on the engine oil level. (You may also notice oil smoke out the exhaust as well).
Unfortunately it looks like a trip to the dealer for them to check what the engine management is saying.

Your motor probably runs in "failsafe" mode (won't go past 3000rpm in highest gear), but in that case the ECU warning light should also come on (which might also be broken ofcourse).

Try releasing and reconnecting the battery (-connectors), which should "reset" any fault-codes in the ECU and see if the TDI power is back. Please note that the "cause" of the ECU faultcodes will probably put the motor back in "failsafe" mode within minutes ! But at least you've verified that your motor runs in "failsafe" mode due to serious faultcodes in the ECU.

You should have a dealer/expert read the ECU faultcodes using VAGCOM to determine the cause. A dealer will charge something like 50~60$ for it.

Since it's a 1.9TDI my best guess is that's it a broken N75 turbo-valve (common TDI issue, replacing the part yourself will cost less than $30 and 15 minutes). When the dealer suggests a complete replacement of the Turbo-unit (quite expensive), please have a TDI-expert do an 2nd opinion ...

sounds like a very common problem on turbo vag vehicles,the variable vains are sticking in the turbo,your fault code would have said....turbo boost pressure not reached.....common with v v t turbos,run a good quality fuel cleaner through it ,if that doesnt work then a new turbo is the only cure