Hey Guys I just bought a 99 Mountaineer and everything fine and good till I got home and drove it the next day and the Check Engine light came on. I checked the Codes and they came up as p0171 and p0174 so lean on each bank. I will change the fuel filter to see if that will help. But I would like a Vacum diagram for a 99 mountaineer with the 5.0l. so I can start chasing down that down before I head home. thank you guys.