New here with a Hummer H2

I am new here to the group and was hoping to find many other folks having issues with their Hummer H2 so I can pick your brain. Lol. Maybe I am not navigating the site well. I have a 2004 H2 that I’ve had since her birth. So I did not inherit anyone else’s problems. Boy is she giving me fits this year. I guess I’m just needing a bit of encouragement at the moment. She has a Vortec 6.0L with the engine identifier of U. I say that because I have been sold the wrong parts over and over. I have GM’s Mode 6 code list but some of mine are not on their list. So yes, I’m a bit frustrated. Anyone here still have their H2 on the road?