What problems can occur from not having a MAP sensor repaired?

Remember GIGO - Garbage In, Garbage Out. The vehicle sensors act the like the engines eyes and ears helping it make the most of its driving conditions. Consequently, the Powertrain Control Module (PCM) can't do this if the inputs it receives are faulty or missing. For example, the engine control system will not go into "closed loop," if the PCM does not receive a good signal from the coolant sensor or oxygen sensor. Nor can it balance the fuel mixture correctly if it does not receive good inputs from the throttle position sensor, MAP sensor or airflow sensor. A MAP sensor (manifold absolute pressure) is one of the sensors used in an internal combustion engine's electronic control system. The manifold absolute pressure measurement is critical to an engine's electronic control unit (ECU) in order to calculate fuel and spark requirements. Accurate and precise air massmeasurement is required to meter fuel mass to achieve acceptable emission control under all operating conditions. The MAP sensor measures the "absolute pressure" (not manifold vacuum) in the engine's intake manifold. The mass of air entering the engine is directly proportional to its density. Density is directly proportional to the air's absolute pressure, and inversely proportional to the air's absolute temperature. hesitation when accelerating, elevated emissions and poor engine performance. The engine will run with a bad MAP sensor, but it will run poorly. Some PCMs can substitute "estimated data" for a missing or out of range MAP signal, but engine performance will be drastically reduced.