The other day my '95 wouldn't return to idle speed as usual. Seemed to take 5 to ten seconds to finally go down to it's normal 800 or so RPM. I removed the plastic piece that goes to the air flow sensor off of the throttle body and applied a very generous dose of WD40 to the inside and to the spring/shaft assembly on the outside. After letting it soak in for an hour I re-installed the plastic piece and took a test drive. Problem solved? Maybe the throttle bypass valve was a a bit sticky?

 

Idle air control valves can be sticky as well with the OEM plumbing in place. Throttle body cleaner can help.

 

So far the WD40 drenching has fixed the problem. The WD is pretty innocuous and won't harm anything. If the problem comes back I'll try the throttle body cleaner. Thanks for the suggestion.

 

Crusty carbon and oil buildup gums it up and can cause it not to seal completely or to not open completely.