My '99 323i (E46) seems to be running fine even though the engine light comes on (occasionally it doesn't come on) indicating a 'pedal position' problem. The code using an ODB II Scan Tool says, "P1624" which my mechanic tells me indicates something wrong with the accelerator. Since it drives fine he expects it is a faulty sensor. Is replacing the sensor a difficult operation I should hire the specialist to do or could I possibly to it myself? I would need to know what part to order.

I'm wondering if it is at all related to a couple of other things that have cropped up recently: My temperature gauge will often peg all the way as high as it can go when the engine is not even hot. If I turn off the the key and turn it on again the gauge returns to functioning properly. Also, my heater is acting up. It doesn't even work most of the time when set to "Auto". Air blows as if it is doing it's job to reach the temperature chosen (80) but the air isn't the least bit warm, let alone hot. If I choose one of the directional buttons, such as windshield or dash/face, I can usually get some warm air but it doesn't seem as warm as it should be for the temperature setting.

These are all probably unrelated but they started acting up in close succession so I just thought I'd see if it sounds familiar to anyone.