So straight to the point.  My car is a bone stock automatic.  When I put it
in gear (reverse or forward, just as long as it isn't in park) and continue
to idle, my car begins to idle roughly.  When I turn on the A/C a similar
thing happens, but rougher.  Also (although possibly unrelated), when I sit
for a while (like at a Drive-Thru) or if I am going from 70 mph down to 35
(getting off at an exit from a major interstate, for instance), my SES light
comes on.  When I'm idling, I can predict when the light will come on
because the rough idling I mentioned earlier eases up a little bit, and the
engine's idle sound becomes slightly higher pitched and slightly smoother.
Anyone have any guesses as to what kind of problems my car is having?
Thanks.
-Ben