The second filter isn't getting fuel when its tough to start? If the first filter is full of crud then I think you may have a tank rust/contamination issue.
Of the three FJ60's I've owned, I've never had a vapor lock problem. That's in Boulder on the hotest day of the summer, engine hot. I don't think your problem is a design flaw such as the fuel line too close to the block. Is it stock? Is the fuel line mounted on rigid standoffs? Have you...