i have a 06 g35 coupe 6mt, the car will start, but if i drive it around and shuts it off, it won't start back up, ill have to let it sit for a good few hours then it ill starts back up. i have already replaced the bcm and nats antenna. also had someone that works at the dealer who couldn't find the issue

 

Ohh I misunderstood what you were saying in the other post. So it drives around just fine but when you shut it off it won't restart for a couple hours yes?

That is a symptom of a failing starter, the solenoid becomes heat soaked and will not engage sometimes when it's really old and in need of a replacement. Typically it won't make ANY sound, not even the autible CLICK like it would if the battery was bad.

In the other post I thought you said the vehicle would stall out while driving.

Still get the battery load bank tested though in case it actually is the culprit and the test is usually free. Testing the starter is a bitch because by the time you get it off and down for testing it's already cooled down and working just fine...

I've simulated heat soak before by using a heat gun to heat up the starter solenoid but you really need to know what you're doing and have an infrared heat gun so you don't just fry the thing. IR scan the starter first when on the vehicle to get a baseline temp to reach then use a heat gun to simulate that same heat while it's on a test bench.

Good luck finding someone locally who will actually do that though

 

Mine was doing this and then failed within a week. Good thing I ordered one on Rockauto prematurely.