Cirrus LXi cant go higher than 170Km/H
 

Hi i have an Chrysler Cirrus LXi 1998 V6 2.5L

and when ive tried to reach my top speed , rpm was at like 6 , and at 170Km/H it drop to 3 and i wasnt able to go faster , im sure thats is lock at 170Km/H (like it wont go higher(sorry for my bad english im french)) and i want to know how i can ''unlock'' this **** , and i was riding with my friend who have a nissan maxima and a mazda 6 , and they have no problem to reach 200Km/H , so i feel like ''aww im so not good :( ''