Not sure if anyone can help but here's my situation.

I have a 91 RS V6 3.1L Automatic. It's unaltered.

I've had it parked for 6 years. I got out and let it idle or drive it every week or so. It starts right up every time. No problem. And drives really well. I bought a new battery for it a couple months ago.

After buying a 2010 Camaro and driving it for a couple years, I decided I want to go retro and drive my 91 for a while. So here's my problem.

Out of the blue, I go out and start it up. After 5 or 6 minutes of running (either in idle or driving) it dies. I lose all power as if I had no battery in the car. After 10 or 20 minutes, all power is restored and it starts right up and drives great.

Then the cycle continues. Start, runs for 5 or 6, dies. 10 or 20 minutes later starts right up, full power restored and runs fine.

I have no flippin idea what the problem is.... any ideas here?

Thanks in advance.

Mike