A lot of my tuning issues have come down to an air filter that wasnt that dirty, just a lot of onroad use. So i didnt change it in a long time. I noticed a huge difference in how much more amazing it ran when i had no filter on because i forgot to install it. It ran so good without a filter. So that led me to putting a new filter on and the engine ran great. My tuning issues and running issues have come down to the filter. The tune and running was so much more consistent with a new filter on it. It wasnt oiled either. I never knew the extent at which the filter can affect tune and running so much. I always wondered and now I know. I always changed filters for maintenance and health of the engine but it has a big affect on tune.