Hi - I have a 1994 Oldsmobile Delta 88 with 70 thousand miles on it -  that
has a peculiar problem.

When the engine is cold and is started up, it idles at around 2000 rpm as
indicated on the tachometer which is normal - however.....

Occasionally, I can travel up to 60 miles or more on the freeway and the
engine will still want to idle at 2000 and up to 3000 rpm when I get off of
the freeway and am stopped at a traffic light.  Stepping hard on the
accelerator and releasing it does not have any effect on the engine speed.

If I pull off the road and  turn the engine off and then re-start it again
about 10 seconds later, the engine will behave normally - that is at idle at
approx. 800 rpm for the rest of my trip.

I have looked under the hood when the engine is idling at 2000 rpm + and
found that the throttle is hard against the idle stop screw and that the
cruise control cable is slack.

Nothing has shown up when the car is connected to an OBD computer.

I thought that the "throttle position sensor" could have been at fault and
so changed it but the problem still exists.

I've also cleaned the internal throttle body and linkage.

Any clues?

Thanks

--jj