I hope Im in the right place...

A couple weeks ago i started getting a CEL and missfire codes. I have a Diablo tuner and can watch 6 missfire in real time.

I have swapped plugs, wires, coils, injectors individually and each time it stayed the same.
I have about 170 lbs of compression, strong spark, and strong injector pulses.
Today i changed the intake manifold gasket since others have found it to fix similar problems.
My wife did just recently watch the "real time data" and didnt get any miss on the highway but it came back at idle when I exited.

I am completely at a loss. Please help!

 

Did you try flashing back to the stock tune to see if it went away???

If not, I see you have the E3 plugs listed in your Sig. I would replace those with some original AC Delco's gaped to .040

The E3's will do nothing for your truck and may possibly be causing the missfire.

 

The intake gaskets with the green orings are thicker than the older orange style, but I have seen many truck manifolds warp and you may still be sucking air with temp changes. If you have ruled out the basics as you say you have, Id ****** the intake off, pop the fuel rail and injectors out and put some 80 grit on a 2x4 and sand over the mating surface a few times to see if you see any high/low spots. If so, you can sand the warp out or replace the manifold IF that is what you find.

 

A clogged cat will pick on the weakest cylinder, and cause misfires. Just one more thing for you to check.