Volkswagen: VW Passat SE 1.9 TDi Engine No. AFN849200, vw passat, wheel bearing

Question
Registered 2.9.99 107,000 miles to date. Fully serviced, recent oil & filter change including air & fuel filter (K&N replacement air filter).
Car starts imediately hot or cold & can cruise at 80 - 100 mph but, when slowed down in traffic the acceleration is so poor we are often left behind. It also feels as if there is not enough fuel available as it feels as though it is being held back.  I am sure it should run more freely than it does. It does not use any oil, & there is no smoke evident. Our local garage has checked it but has not found anything wrong. We have also treated it to some Redex deisel treatment which, for a while seemed to improve things, but at the moment acceleration is dreadful, please can you advise.

Equally annoying, and also checked, is a wheel bearing type hum and drone from the front wheels. I replaced the discs and pads recently with Brembo discs and Ferodo pads. The noise can also be described as a hollow knocking sound & is constant what ever the road surface, so I have ruled out tyre noise as this does vary.

Not having driven a similar car, I cannot draw comparisons, but feel that although my local garage were unable to find any problems, all is not right. Should I sell the car or try to find out exactly what is wrong in both departments?

It's difficult to make a decision as, despite the mileage and age, the car looks almost as new.

P.S. it has had the VW recall for the lower suspension arm checked, all was okay.

I look forward to your reply.

Answer
it sounds like a possible wheel bearing, i would keep driving it and let the noise become more obvious and therefore easier to locate. as for the running issue, i would advise replacing the air mass meter, this is a common problem. it uses the readings from the air mass meter to calculate the amount of fuel required. if the reading is wrong, the fueling will be wrong. the air mass meter is available from vw main agents for around £80. this cures flat running in 95% of cases. (the air mass meter is exchange, so they will charge a fee to ensure you return the old unit) i would not sell the car as it should run well into it's 200,000 miles, so it is still young by definition. (have sold one before with 245,000 miles and it is still going strong!) agents will need full chassis number and engine number to get correct part.