Engine reving high after driving

I just changed my O2 sensor in my 91 olds calais 2.3 quad 4 and it starts fine and then after a short ride when i put in the park (or neutral) the engine revs high. But when i put it in neutral and let it
roll to approx. 5 mph the reving goes back to normal but when i stop it revs high again. Any help is appriciated. Thanks in advance.
Posted using the http://www.autoforumz.com interface, at author's request
Articles individually checked for conformance to usenet standards
  Click to see the full signature.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.