Oil stain on driver side carpet
 

Hey guys the other day I was cleaning my 91 rx7 when I came across oil stains on the carpet looked for a leak couldn't find out but under the steering wheel under the dash to be technical I saw it was oily. Can anybody tell where and what this is and how to solve it. Thanks!!

Only fluid that can possibly be around that location may be either clutch or brake fluid.(maybe coolant if the heater core is leaking inside the cabin).
If it is oil then maybe someone had a mechanical oil gauge hooked up in the car previously and the hose going to the unit and sender was not properly installed.

A good rug cleaner can fix it.But it would take a fair amount of elbow grease..pardon the grease reference.

Never seen it myself, but I've heard oil can make its way up the speedometer cable to the back of the gauge cluster. If you can pull your gauge cluster, you can see if that's the culprit.

What cause that though?

There is a seal in there somewhere that just wears out over time. It's probably in the sender bolted to the trans. Never seen any instructions for replacing the seal itself, so it may require a replacement part.