TTi shorty headers v ministarter

Darter6, I'm pretty sure that I have good grounds. My battery is in the trunk, but I have a lug in the engine bay hooked directly to the battery negative. I have ground strap from the engine block to the firewall, and also another ground from that negative battery lug to the starter case. That said, I'll check that ground to the starter.

Question: why would it start easily when cold and harder when hot due to a bad ground? Wouldn't that make it hard to start at any temp?

Brian