Just a warning here guys - I recently suffered from a distinct lack of ' low end ' power, having changed the EGR valve and MAF based on the ECU codes it didn't resolve the issue.
However it turned out to be the replacement ' aftermarket MAF ' that prolonged the issue, I replaced with the genuine Siemens / VDO component and the issue is resolved, the car feels totally transformed
I had a total loss of power too, and on some mornings would just slump into limp mode...
Replaced the battery which was naffed anyway, replaced all the filters pollen (very bad), fuel, and air.
It was when doing the air filter i noticed there was something up. The filter holder was full of water in the collection whole....
Also then noticed the MAF was in an awful state, with the sensor completely eroded.
Was put off the copy MAF's by people on here, and went direct to dealer, got the Siemans one, Happy days. Like a new car.. MPG flying it.
However discovered why the water was getting to filter housing was the wheel arch liner was missing, so collecting all the waterspray from wheel!!!!
Replaced liner and all is well, now i have got to root of the problem....
Another way i increased MPG was using Millers fuel additive bumped me up by nearly 5MPG on urban driving...
getting 45MPG urban......