YOU SAID:

we're driving fast in my car

INTO JAPANESE

我々 は、私の車で高速運転しています。

BACK INTO ENGLISH

We have high speed driving in my car.

INTO JAPANESE

我々 は高速私の車の運転があります。

BACK INTO ENGLISH

We are driving high speed I.

INTO JAPANESE

高速を運転している私。

BACK INTO ENGLISH

My high speed driving.

INTO JAPANESE

私の高速運転。

BACK INTO ENGLISH

My high speed driving.