Starts in morning but not after it warms up outside

I have a friends that has a Lexus I believe it's a lx
470 but anyways the problem is it starts in the
morning but once it warms up outside it just turns
over and won't start mechanic change fuel pump
and relay and check the sensor behind tail light
nothing has fixed it. It doesn't have this problem in
fall or winter just when the temperature outside is
warm.