I think that sensor is normally mounted under the air box on the corner nearest the intake side. You said the previous owner had mounted a getto air intake. Either it has no mounting point for the sensor or he didn't bother to put it back where it belongs.

 

He just tied the sensor to the intake. I checked the connections and they were ok.

 

well, that sensor is supposed to go inside the intake tract, hence used for the calculation of the air going into the engine. if its just sitting outside, it will only read the ambient air (engine bay temperature) which can cause issues. any intake which is somewhat reputable will have a bung designated for the iat sensor. i'd hurry and get another intake or buy a stock one and hook it up properly.