This is an unusual topic for me but since I never really found a single article on the web that explained these concepts to me, I thought I’d cobble together some knowledge from my recent used car purchase. Enjoy! Background: my wife and I owned an old, 1997 Pathfinder that recently failed emissions due to a faulty knock sensor. Repairs would cost more than the car was worth, so we decided it was time for a new, used car and […]