AFM Temp sensor causes bad cold idle?

[DaniTD]

Well, TPS new and properly adjusted. New sparkplugs, new ICV and new Blue temperature sensor.
But when engine is cold, I never saw a 1100-1000 rpm idle. The car starts and goes to about 700 rpm, and it feels uncomfortable with vibrations. If I press the accelerator to 1000rpm it feels much better, but when you release the pedal the engine hunts about 600-700 and then stabilizes.. The thing is worse when the outside temperature is colder, like 10ºC or below. Even you can feel a little stumble every 5 seconds or so, nothing tremendous but uncomfortable, and that when the engine is warm too.
Also I always felt that in summer, with temperatures over 25ºC - 30ºC the engine runs much smoother, even when warm, and with no stumbles I think.

The engine is an M40 no catalyzed, 1.8 liter. Yesterday I tested the air temperature sensor on the AFM with a multimeter between pins 4 and 5 on the round connector. The room temperature was about 20-21ºC, so the resistor should have an output of about 2200-2600 Ohm, but I got 409 Ohm and that means the ECU thinks air temp is about 70ºC so I think I don´t new an ice cube test.

I have two questions: Can be this screwed air temp sensor guilty of poor idle on cold? Would get the normal 1000-1100 rpm idle when very cold if I change this?

The second question is: I saw that on old AFM from M10 and so, the air temp sensor can be removed in one piece so you can just cut the old resistor and solder a new one, as I know people that made this and went well. But on this AFM it seems that the air temp sensor can´t be removed that easy from the casing so I would have to cut and solder on the way, or I am wrong?

Thank you very much!

[Grrrmachine]

The symptoms sound much more like an air leak than any sensor-related issue. I don't remember hearing about any failed AFM temp sensors causing idle issues.

No idea on AFM repairs, unfortunately.