hi, i had exactly the same problem on same car 1999. i found a simple answer that worked for me now my car runs like a dream. If you are prone to changing gears late and pulling off before the enigine has warmed then the answer is to unplug your battery for half hour. This resets the computer and then when you drive it after make sure you warm the car first then change gears early. I have always sped around in mine and the car thinks that this is how you always drive and changes thing ie the revs to cope with this.
hope this works for you as my car is lovely to drive now, ive been trying to sort the problem for past year now and spent lots of money on changing all sorts that just didnt need changing.
good luck
Toni
June 2008