The issue is Fram oil filters, mostly. Even though I was a user of Fram oil filters for over 20 years, the information provided by various studies and websites have convinced to me not purchase Fram oil filters in the future. Good, relatively unbiased info concerning oil and air filters is Bobistheoilguy.com. There is an on-going thread on Fram air filters you might be interested in, as well as an ISO standard air filter study that measured actual performance of several air filters in a Duramax diesel truck engine. Oddly enough, Fram was not one of the brands they tested.