What is the free fix?

Twisting the board and checking the idle? I have narrowed the search on my 380 SE to the idle control computer, but even after I re soldered the connections, it did not fix it. The leak issue may exist, my idle is OK some of the time, then races up to 1500 other times. Its completely random, sometimes it races the it drops down to 200 rpm and car amost stalls for a moment, then it climbs again. Most of thwe time these days it is high (1500 rpm).

I have a 380 sl from which I should be able to borrow a computer, but cannot find it on the SL, I even pulled the underside of the dash and passenger side kickplate, but can't find it.

Cheers,

John