Hi
As you may or may not know I have a 1999 Golf TDI. I just got back from a long trip a week or so ago (1000+ Kms) of very hard driving on the engine (straight highway, at good speed, then country highways with winding roads, heavy acceleration, going up steep hills with 4 people and luggage, using engine compression to go down hills - automatic transmission). Anyhow, it was a nice trip, got good fuel economy... but now I have noticed my fuel economy is being sustained, and I am back to my normal city and short distance highway driving.... is this normal, was my engine "cleaned out" per say? I am happy, so there is no problem, just wanted to know if I should try to work in a good long trip every few months or something. I put on enough KMs in the year, but its mostly short distances, and a lot of starting/stopping (the reason why the automatic wasn't looking too bad when I found out I could only get a hold of an automatic TDI Golf).
I noticed that power delivery was a little sluggish at first, but by the end of the trip the engine seemed a little bit more responsive... I still wish I had a manual transmission for a trip like that; with all the passing, and accelerating, and hill climbing that I was doing... I even considered taking the A/C-less 1991 5 speed Golf, but its 12 year old timing belt, and its less comfortable seats and cabin ambiance swayed my descision (that and my friends would have physically injured me I think), plus why should I take what is now basically my brothers car :-), wouldn't want him drivng the new one you know ;-).
No problems on the trip, the car is now washed and clear of all bug related abuse on the paint. Nary an engine light came on :-), and the little car was praised for having a comfortable cabin (stuck short people in the back... knee room is a smidge too tight for me back there), great A/C system, and a very nice "club like" stereo system.