For the last 5 or so months, my 1993 940 n/t wagon with 133K would start up fine, but periodically hesitate when in 1st gear. It happened more often when the engine was cold, but it would still occur occasionally after accelerating at a stop sign or something. The hesitation could be described as about a 1 or 2 second lapse of time when the engine wouldn't "grab," before it finally did.

Then, in about mid-November, the occasional hesitation started to become more regular. I took it into my mechanic, thinking it was possibly the air mass meter. But my mechanic said he thought it might be the throttle position sensor, so I ordered one of those, had it put in, and that didn't make a difference.

But my mechanic noticed that if he removed the sensor from the blue plug-in pictured below....

http://ctitech.com/users/rlcina/airtempfuel.jpg

....the problem went away. No more hesitation. The check engine light is on, and when I put it in park, the idle revs up to 2K rpm, but that blue sensor that is circled in red in the picture, seems to be where the problem is. I think this is some kind of temperature sensor for the air box, is it not?

Can someone tell me what this part does, why I no longer have the problem when it's unplugged, and where I can get a replacement for whatever it is? Also, am I jeopardizing anything by leaving this unplugged?

Thanks for any responses.