I recently bought an o8 Saab 9-3 1.9 TDI 150 Linear with 40K on the clock.Very occasionally when driving and usually changing down to go round a corner I can take my foot off the accelerator and the car keeps going and seems to pick up speed as if the cruise control has been switched on.I have to brake to slow the car down.I have been back to the garage where the mechanic is Saab trained and he has not found any fault including plugging into the computer.Other than this the car is fine.The car drives fine and as stated this is an intermittent problem.Any ideas ?