Volkswagen Polo looses power if push too much

When was fuel filter laast changed ? Could be leak back in fuel pipes also .When was the timing belt last checked / replaced ?

The car just been in the mechanic, they spent a whole day trying to figure out what was it, didn´t want to pay tons of hours without actually get it fixed. All hoses were checked, they replace a valve that takes diesel excess back to tank, but still doing same cut when I push , just turning OFF even rolling and its back for while.

I´ve found this message in "TDI CLUB-forum" that describes what my car have but the person wants money to tell what is the problem .[i]"This is apparently a very common problem with this engine. The engine runs fine but every so often there is a big loss of power like the turbo has stopped working and the engine management light comes on. When you turn the engine off and restart the fault is clear and everything is ok. Precaution: DO NOT jump to conclusions when attempting to identify the cause of having no power. Don't automatically assume that your turbocharger is broken! When the computer is plugged in there is no fault found or turbo pressure fault. Resulting in the ECU not seeing a proper pressure signal and causing "limp mode" THERE IS ONLY 1(ONE) WAY TO FIX THIS!!!!!!! 1). By doing it yourself! It will take you about 5 min! Using no tools! NO parts needs to be replaced! (wont cost you a cent) I have spend over R12000! But my polo was doing the same (going in to Limp mode) and NO one could help me! But now my TDI is 100% better then ever and using 4.2 L/per 100km at 120km/h And no more (Limp mode) I helped 4 people with this problem to make sure that this is the way to fix this problem and am glad to say ALL 4 TDI's is 100%! Now im asking R1000 to send you the Instractions! NB; please if i send you the Instractions dont tel every one!!!! I first need to make up the R12000 i have lost! You can email me at [email protected] i will then send you my banking details and a copy of my id![/]