Right on top of the throttle body, there's a hose and a smaller thin cable. If you lean over the driver's side strut tower, the cable would be on your right. The thin cable/wire, which has very little slack, runs down towards the air filter box.

What is the purpose of this cable, where does it go, and would it affect the idle?

Why I'm asking:
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The top portion of my cable, where it curves/bends, tends to have a crack on it (i.e., the more you bend it, the larger the tear will get).

I've been having an strange idle problem with my '89 244DL automatic. After driving on the interstate, specifically above 70+mph, and then eventually shifting into either Neutral or Park results in my idle surging from 900'ish to 1500. If I turn off the car and turn it back on ten seconds later, the problem will be gone. This does not happen in daily driving around town. Gas mileage is not affected. I've swapped out the IAC, air intake hoses, cleaned out the throttle body, had my mechanic swap out the TPS and reset the idle, checked for vacuum leaks, and finally, I also swapped out the ECU. The problem still persists which lead me to ask the question above.

Thanks in advance.
Eric Staufer,
'89 244DL 119k