Problems please help....

[mika]

Hi guys!! Would someone please help me solve my problem on my Polo 1.4 8v with 40,000kms. It seems that when I drive at low revs just around 2000 revs the engine misfires a little bit even when I am in the proper gear just when I am accellerating smoothly. If I drive it hard between revs it would drive normally. I cleaned the throttle body, changed the fuel filter, renewed plugs and HT leads with no improvement. I just spent money for nothing. I am now fed up with the trial and error method and when I visited the vw garage and connected with the diagnoser no faults resulted and the technician said that it is all in my mind but I've been driving cars for quite a while now!! Had somebody out there had this problem please.
N.B. sorry for my poor english I am not British!!