Slow_SL55

I have a 03 SL55 and searched the posts and found lots of hot restart issues but none like mine. When cold it starts fine but when it gets hot it does not crank over good cranks very slow. I did a load test on the batteries and they are holding load good put a fan to cool starter and after a few minutes it starts fine. So I figured it was the starter putting heavy load on bat but new starter does the same.WTF

Anybody?

Thanks,