JGR4444

I installed a set of ls2 yukon coils a couple days ago and the car seems to be running a lot smoother. However, i am having problems starting it but it is only when i have been running it. Cold starts, it fires right up... warm motor it will crank but not start... ill let it sit for a second... crank... no start.... let it sit... crank for about 2 seconds and it will fire....

Yes it is grounded correctly and i have TRIPLE checked all the wiring and made sure all the coils matched with the correct spark plugs... i cant figure out what the problem is any ideas?