I have a 2003 Duramax that wont start if the temp outside is hot. Starts fine when the weather is cool. I have to prime it to restart and if it's very hot (90 deg or more) it won't start at all no matter how much I prime it. I had to wait until the evening when it cooled down to prime and restart. Other than that it seems to run just fine. Any ideas?

 

So when you tried starting it turned over fine the same as at night or when cooler out?

 

Yes, it turns over fine. For some reason it's not getting fuel after running on a hot day when I turn it off and go to restart.

 

Check your fuel filter heater element. Gets hot and goes dead like a bad fuel pump.