When it is about to die, how does the exhaust smell? Is it a gassy rich smell, or an acrid lean smell? Have you looked at the tank screen on the pickup? I'd run some fuel into a clear container from the disconnected filter and look for water in the fuel, and I'd hook up the filter backwards and flush it into the container to look for lots of debris.

I think you either have a fuel supply problem, or some electronic component is failing under heat, or there's and electronic or mechanical spark problem, and would diagnose in that order.

Not responsible for advice not taken...