Hi,
I have an 03 (UK) focus zetec TDCi. It now has 26,000 miles on the clock and for the last 8-10,000 miles I have complained to my local dealer that it had become very smoky. There was a lot of black smoke, even under light acceleration.
The dealer has had the car in and changed the EGR (Exhaust Gas Recirculation) Valve - what a difference !!!
The car feels like it did when I first got it, and there is no more smoke. Throttle response is great and it feels MUCH quicker.
I've seen quite a few 02, 52, 03 and 53 reg TDCi's on the road that seem to produce loads of black smoke - if yours does, get it in and get the dealer to change the EGR valve.
Cheers
Geoff