So I've been swapping tunes in my 01 duramax and data logging the results. Mostly tcm tunes but I did try an ecm tune that I found here in the tune library, the No logic 3.0 lb7 tune. Tried it out but couldn't run it, made way too much noise. Sounds like a really cold diesel even though truck was warm. By the time I turned around and made it home I had developed an idle lope in park. Not bad but certainly noticable, goes away when in gear or I turn on the ac. I flashed the ecm with the stock file and it still does it ! Went for a good run, no change still lopes. Let the truck cool down a bit, flashed in my tune that I've been running for years. Still does it...WTF.. I went for a longer drive, now it idles without lope in park but lopes in gear and or when you turn on the ac ! .. Is it possible this could be related to my tcm tune somehow? What tables are commonly used to affect idle stability ? And since I returned it to stock and still had the issue what hard parts could be upset about my tuning adventures?