Can't tell you about the oil stuff but there's 2 sensors for coolant temp on the car. Both are in the crossover. The one on the passenger side of the manifold is for the gauge. The one on the driver side of the manifold is for the EEC. Both have 2 wires. Normally the sensor for the gauge has one wire but for the 4.6 with a plastic crossover there needs to be 2 since the crossover can't be used as a ground.