nhkayaker17
New Member
I replaced the upstream O2 sensor in my 2000 4.0 Ranger. When I reconnected the battery and tried driving it, the transmission shifted hard and the truck had no power. It drove fine in reverse though. The CEL is still on as well. I don't think it matters, but I replaced the oil as well before I started it back up Has anyone had this issue before? Is it a faulty O2 sensor?