I have a 04 yukon denali interceptor with the 6.0. It is running super rough and wanted to do a valve adjustment. I asked dealer to check a few things for me but they didnt give me any answers. I need to know what type of lifters i have and what the best way to adjust them is. On my old cars i went off tdc of cylinder #1 but read recently that it would be better to do it at full lift. So im a little confused. I dont have a lot of time on my hands to really research but when i do have time i try to. I work 2 full time jobs. I tried searching but nothing came up so yall are my last resort. I also do not have a repair manual as i have not been able to find one in stores and just havent had the need, until now, to really look at it. Hope yall can help. Might as well say this now. Has new plugs, wires, air filter, pass exhaust manifold gasket, new battery, and bank 2 sensor 2 o2 sensor fault. Waiting to address that hoping its working properly and telling me somethings wrong up front. Thanks in advance.