It's in the fresh air intake tube, it's called the MASS AIR FLOW SENSOR it is heated and monitored to see how fast it cools by the incoming air. The range is determined by the EMC (computer).Your car can have up to three computers, EMC (engine),BMC,(body)and one for traction control. Some have 4 or 5 depending on year, model, manufacter,Try checking the connection then clean it with tuner cleaner .Clean the mass air flow sensor (ignition off)clean it (cold) with tuner cleaner GENTLY. Don't drop or hit it with anything.The circuit runs on 5volts signal from the EMC and sends the approprate signal back to the EMC. Your vehicle could die if you unplug it while idling( some GM's do).These are general checks not specific to any vehicle.