Idle Problems.

I have a '95 Ford Ranger 4cly with 103k miles and I just cleaned the throttle body and the upper intake manifold (I took both off of the engine). I put everything back together correctly, hoses, sensors etc. But after starting the car it seems to idle weird. I have a tach and usaully it idles at around 750 RPM but know it is idling around 550-600 and it feels like it is going to stall. Some one told me that sometimes the computer needs some time to adjust to knew circumstances (in this case the carbon build being removed and more airflow into the engine). I was wondering if this is true or if I should get my car serviced. Thanks!