That foam is used inside some of the chassis extrusions, presumably to keep brake dust and other contaminants from entering the HVAC. I had the piece that was behind the upper wishbone mount get knocked loose, you can see it back there in the picture. It's a block of foam, the same size as the inside of the extrusion and it's just wedged in there. Looks like there's also a flat piece used on top of some of the extrusions. but I bet a rodent would go for the tunnel-like area inside the aluminum cross member.

You definitely want to purge your garage. If you get a rodent inside the car, they cause all kinds of problems. They chew everything, the wires, the foam, the plastic, they can make nests in there and cause all kinds of havoc, and that's not to mention their waste piling up. All of which generally requires a major tear down to clean and remedy.

There are some threads with horrifying examples of this stuff and some good preventative measures.

 

My ex wife burned up my 69 427 Chevy Caprice by starting it after mice made a nest in the carb. I never forgave her which is probably why we divorced shortly after.

Moral of the story is make sure you get that sucker(s) or you will end up being sorry.

 

If it's not too much of a pain, you might try pulling off the plastic sill cover inside. Under that sill panel will be a space that contains foam blocks. The foam goes all the way to the front of the rear wheel well, so the critter might have gotten in there. You should be able to seal that area off so that he can't get back in there.

 

Very tardy update: I found out where the foam rubber came from after pulling the front passenger wheel liner - see photo. I'm guessing that's an AC line that's now partially naked?

Anyhow, I pulled off all the other wheel liners, the engine access panel, and the door sill panels and I could find no other evidence of its presence. I know, for sure, that it has been in the engine compartment because I saw paw prints on the engine covers, the airbox, and a couple other places that were also covered in dust. I found no droppings of any kind anywhere - thought I was going to at least see some on the engine access panel, but nope.

I even drove it around for a couple miles with all the wheel liners and the access panel off, but all I think all I may have accomplished was to lose a few of the quick release slide clips for the access panel. :facepalm

I think it may still be loose somewhere in the garage as one of the rat bait blocks disappeared a couple days ago. I was hoping my bro and I would be able to work on cleaning up the garage over the holiday break since we were both off, but I ended up with the flu.

 

Time for war. I would put mouse killer in the garage and in the car itself. Under in and around. Big chunks,, do you have wood rats in the area? Chipmunk or squirrels (red) could do the same thing. I would start looking for a nest also. When I bought my Esprit it had been in storage for over 15 years. We found a large nest in the left rear corner. Lucky for me they didn't do any damage other then nibbling on the interior light harness wire. But dropping were found in the binnacle also. Now I keep poison everywhere in the garage and car Randomly I let my cats in the garage after I pick up the poison. The message is,, you are not welcome here to the critters.