Re: Rough Start
If your engine idles rough or stalls, your Ford Bronco might have a bad Manifold Air Pressure Sensor. You will have to test the MAP sensor. Follow the below steps to test the MAP sensor.
1) Locate the MAP sensor and disconnect the wiring harness from the MAP sensor. Each end of the sensor has a small tap. Pry the harness off the tap and pull the harness free of the MAP sensor.
2) Place a jumper wire between the terminals on the wiring harness and the terminals on the MAP sensor. Make sure the jumpers are bare wire and that they do not touch each other or any other metal component on the Bronco.
3) Turn the Bronco's key to the "On" position but do not start the engine. Place the leads of your multimeter onto the bare jumper wires and take a voltage reading. The voltage should reflect between 4.5 to 5.0 volts.
4) Start the engine and let it warm up to normal operating temperature. Test the voltage again. The voltage reading should be different. Have an assistant rev the engine several times. The voltage reading should fluctuate with the revving of the engine. If it does not, the MAP sensor is defective.