cordoba tdi flat spots / poor acceleration

Can anyone help ? I have a '98 Seat Cordoba Vario TDi. Basically there appears to be very little power below 1700-2000rpm, sometimes bogging down, but will accelerate quite hard above this rev range. Once above 2000rpm it "hesitates" around 2250, 2500, 2750 & 3000rpm with acceleration dropping off above this. This is more noticeable in 3rd & 4th gears and can be a real pain when trying to overtake i.e hard on the throttle. On motorways it will sit quite happily at 60 - 80 mph accelerating fairly briskly between the two speeds in 5th as long as you're not too hard on the throttle. The other thing I have noticed is that at night when being followed by another car with its headlights on I am laying down more smoke when these "hesitations" occur. Car is returning around 50mpg on mainly motorway runs.

Hello
Any DTCs?
You could have a weak/faulty fuel pressure regulator (FPR) or pump. Some TDIs require diesel additive to keep fuel pump healthy due to sulfur composition in fuel.
Cheers

sounds like a classic throttle position sensor prob - check it, & if good, then i'd check the map or maf depending on which yours has.