Good afternoon,
my 91 940SE turbowagon has 130k miles. runs perfectly except for a minor glitch:

AFTER A HARD ACCELERATION IT IDLES HIGH

Under normal driving, even with highway speeds, when I come to a stop the engine idles normally.
But if during that driving I have pressed the accelerator hard, causing the turbo to go on full boost, or the transmission to down shift, when I come to a stop, the engine will idle high at around 1500-1700. If I turn the engine off and then back on it goes back to normal. It does not matter if the hard acceleration was 2 minutes or 2 hours before coming to a stop, the engine will remember it and keep idling fast!!!

I have checked the accelerator cable and linkage. The TPS does the click and the throttle body is clean.

I think that it might be something that has to do with the rich-lean affair. The O2 sensor is new too (BOSCH), and the spark plugs are denso iridium. Maybe Air Mass Sensor? I am clueless...

...and I can bet that somebody out there has exactly the same issue.

Any ideas?

Thank you ,
Davide