I am planning on reading voltage from a vehicle's MAP sensor (Manifold Absolute Pressure) to make a vacuum gauge. Conveniently the sensor's output is 0-5v. I am planning on splicing into the output of this sensor and running it to an analog pin on the Andruino.
My concern is if there is a chance of feeding voltage back into the vehicle's wiring as this sensor goes to the engine computer and used to determine fuel regulation. Is this going to be a problem?