re. Crazy Idle

[Ben Swann]

I hazard a guess that your throttle body switch is flaky - sometimes it contacts and sometimes it doesn't.

Ben
2 - '87 5kcstq avants with to many idle anomolies to stick a shake at - from ISVs and idle screw o-rings to throttle switches.

'85 4kq - same type of stuff, different part numbers.

[My 90 200 TQW's idle has been acting strange lately.  After it has been
driven, say 25 miles or thereabouts (meaning the car is fully warmed up),
the engine speed goes up from its customary idle at about 100 rpm to close
to 3000 and sometimes stays there for sometime before it comes down.  I
could be at an intersection, with the gear in neutral and watch the engine
race.  The car behaves normally for a while after the engine is turned off
and back again, but the problem sometimes comes back.  Note that this does
not always happen.   My mechanic is stumped.  He has checked the idle motor
and ed and it works OK.  He kept the car for a day and drove it around. The
car did this once when he was out to buy lunch, and did not repeat after he
returned to
the shop.

 Has anyone had a similar problem and found a fix ?]