I removed the center storage box between the seats. Saw a trap door into the tunnel and removed the plate. This is what I found.

This is directly under the back pad and against the firewall. All I can figure is that water collected here, maybe with the car on a slight nose up angle, and sat for a few years.

The good news is that it appears to be surface rust and, so far, passed the screwdriver poke test. Challenge now is to scrape the crap off in a tight area and control the damage.

Can't you pour POR15 into that area and seal it that way?

Just in case you were to get more water in the area, how about a drain hole?? Just a thought.
CCLINROTOROOTER

My understanding of POR-15 is that even though it does encapsulate rust, keeping the air away, the rust process still continues. Just more slowly. I plan on cleaning the area as good as possible, treating it with a conversion solution, and then coat with something like POR-15.

I suppose a drain hole would not hurt. I suspect that the damage is from the PPO. Under the PO's care the care was never driven in the rain and always under cover in wet weather. I know the car sat for a long time prior to the PO's purchase and suspect that there was a lot of water in that part of the tunnel during that time. I keep the car covered and rarely drive it in the rain so I do not expect the problem to continue.

-Jeff

I had some rust like that in mine, I used Jasco to neutralize the rust and then I used POR15 to coat is afterwards. I hope it all works like they advertise.