3.4L camaro won't start sometimes when hot?

My sister has a 95 camaro with the 3.4L. Occationally after the car has been driven for a while, if you go to start it back up after its warm it won't start. If you let the car cool down it will start. We thought that maybe the starter was going out so we replaced that and it still does it. So hopefully someone can help me out. Thanks in advance.

did you replace the heat shilde back onto the new starter from the old starter? Heat is the major enemy of electronics on cars. It also could be something else cause like the ICM or PCM.