If your vehicle is showing hard to start when engine is hot, here are the most likely causes and the parts you'll need to fix each one.
The sensor falsely tells the engine computer that the engine is still cold. The computer responds by injecting too much fuel, effectively flooding the hot engine and making it hard to start.
The starter motor absorbs excessive heat from the exhaust, which increases its internal electrical resistance. This causes a slow, weak crank when hot. This often happens if a heat shield was left off during recent exhaust or starter work.
Worn injectors can drip fuel into the engine cylinders after you turn the car off. When you try to restart a hot engine after it has been sitting for a short time, the cylinders are flooded with excess fuel.
Electronic sensors can develop microscopic internal cracks. As the engine heats up, thermal expansion causes these cracks to separate and break the circuit, cutting off the spark or fuel signal until the engine cools down.
A failing fuel pressure regulator or fuel pump check valve lets fuel pressure drop immediately after shutdown. The hot engine bay causes the unpressurized fuel in the lines to boil into vapor, starving the engine of liquid fuel on restart.
A stuck open purge valve allows excessive fuel vapors from the gas tank to be sucked into the intake manifold while the car sits hot, creating a rich condition that floods the engine.
Ignition components can break down internally due to repeated heat cycles. They may provide a strong spark when cold, but a weak or non-existent spark when the engine bay is hot.