You would have to get to it via the trunk. And no that's not the actual fuel tank it's part of the tub. The tank sits inside that hump.

Was back in town and did some work. I had to take off the rear parcel shelf to get to the ground behind the drivers seat. You technically can access it from the trunk, but the access is so tiny I couldn't possibly do anything. Anyway, I took off my rear parcel shelf by following rollbar install guides, cleaned the ground, verified low resistance with a voltmeter, and everything looked good.

However, I still have the same problem. Drove it for an hour today, everything was good, kept driving (didn't stop) and it started acting up. I really need a good shop in Atlanta I can take this to because I am out of my depth and I have no idea what else it could be.

Have you closely inspected the bulkhead electrical connector on the inside and outside of the tank? I had the inner one fail.

I've replaced the entire sending unit. Doesn't that include that connector?

It doesn't include the vehicle side that plugs into the top.

This sounds like an interesting problem. Since the one constant is time and pressure, I'm wondering - how do your fuel lines look? I've never heard of this, but I'm wondering if the fuel getting heating up is swelling a line and pinching it off? I've never heard of this being a problem, but just spitballing an idea. I would also give RSpeed another shot, they're typically very good but this is definitely not a typical problem - the other local shop is Miata Afterworld.

Solved??
 

Did you ever figure this out? My cars doing the exact same thing and we are so lost