the car was running extremly rich and it throwing bad map sensor code. i discovered the the map sensor vacuum line was unplugged, i also replaced the map sensor about a year ago, i plugged the vacuum tube back in and now the car throws code 44,exhaust too lean, the car runs now very lean until it stalls. just wondering if the map sensor could of been defective. i also have a vacuum tube that isn't hooked up to anything and i can't find where it is supposed to connect. there are 2 vacuum lines coming from the left rear part of the engine bay, they are wrapped into the main wiring harness. one line is connected to a sensor with a elecrical plug on it, then from there it connects to the front left side of the throttle body. the other line i mentioned isn't connected to anything. i plugged the map sensor into the back of the throttlebody. i assume the right side of the throttlebody vac port is for the intake. ecu had been replaced recently also. will a bad o2 sensor cause the motor to run lean?