2008 Chevy Silverado 5.3 misfire only at idle on #2

It runs great going down the road but if I stop at a red light it starts to miss I already replaced the coil spark plugs & wires and injector I’m lost

Have you run a compression test on the engine? That cylinder may be a bit worn and the low compression is causing a mis-fire. What did the sparkplug from #2 look like when removed?

And how do you know that there is a mis-fire on #2? Did the check engine light go on? Did you scan the codes and get a P0302? Or do you just feel it?

I bet that cylinder is one of the cylinders with a collapsible AFM lifter…but I don’t know for certain. If so, could be the cause. GM had a lot of problems with those lifters, especially in 07 and 08.

A test with a vacuum gauge could be a good precursor to running a compression test.

If not low compression then maybe a weak valve spring. I’ve seen this on Chevys a few times.
A vacuum gauge would show a weak or broken spring.