I was pulled over driving my sister's car. The car is legal, but her license is suspended. They pulled me over thinking I was her, driving illegally. I have a licence and am legally allowed to drive. They have me no reason for the stop. Asked me to do field sobriety, I did and passed. Then I did 4 brethalizer tests, and they told me I was trying to manipulate it, so they detained me for an hour and a half. They tried to give me another breathalizer and I refused, saying they had no right. They then charged me with a DUI.
You need to talk to a lawyer who handles dui in your county because they had to have found something to charge you with a dui.
If they suspect you are driving while intoxicated--and they will doiubtless say you were driving erratically--they can pull you over.